Linux Distros Unpatched Vulnerability : CVE-2026-3904

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(302199);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/04/14");

  script_cve_id("CVE-2026-3904");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-3904");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the
    GNU C Library version 2.36 under high load on x86_64 systems, the client may call memcmp on inputs that
    are concurrently modified by other processes or threads and crash. The nscd client in the GNU C Library
    uses the memcmp function with inputs that may be concurrently modified by another thread, potentially
    resulting in spurious cache misses, which in itself is not a security issue. However in the GNU C Library
    version 2.36 an optimized implementation of memcmp was introduced for x86_64 which could crash when
    invoked with such undefined behaviour, turning this into a potential crash of the nscd client and the
    application that uses it. This implementation was backported to the 2.35 branch, making the nscd client in
    that branch vulnerable as well. Subsequently, the fix for this issue was backported to all vulnerable
    branches in the GNU C Library repository. It is advised that distributions that may have cherry-picked the
    memcpy SSE2 optimization in their copy of the GNU C Library, also apply the fix to avoid the potential
    crash in the nscd client. (CVE-2026-3904)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://ubuntu.com/security/CVE-2026-3904");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-3904");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/02/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/03/13");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:25.10");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:eglibc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:glibc");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info2.nasl", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Ubuntu Linux-14.04", "Host/OS/Ubuntu Linux-16.04", "Host/OS/Ubuntu Linux-18.04", "Host/OS/Ubuntu Linux-20.04", "Host/OS/Ubuntu Linux-22.04", "Host/OS/Ubuntu Linux-24.04", "Host/OS/Ubuntu Linux-25.10");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Ubuntu Linux-14.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14.04",
        "pkgs": [
          {"reference": "eglibc-source"},
          {"reference": "glibc-doc"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc0.1"},
          {"reference": "libc0.1-dbg"},
          {"reference": "libc0.1-dev"},
          {"reference": "libc0.1-dev-i386"},
          {"reference": "libc0.1-i386"},
          {"reference": "libc0.1-i686"},
          {"reference": "libc0.1-pic"},
          {"reference": "libc0.1-prof"},
          {"reference": "libc0.1-udeb"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-i686"},
          {"reference": "libc0.3-pic"},
          {"reference": "libc0.3-prof"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc0.3-xen"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-armel"},
          {"reference": "libc6-armhf"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-armel"},
          {"reference": "libc6-dev-armhf"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-i686"},
          {"reference": "libc6-loongson2f"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-pic"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-prof"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6-xen"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-alphaev67"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-pic"},
          {"reference": "libc6.1-prof"},
          {"reference": "libc6.1-udeb"},
          {"reference": "libnss-dns-udeb"},
          {"reference": "libnss-files-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "multiarch-support"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-16.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "16.04",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.1"},
          {"reference": "libc0.1-dbg"},
          {"reference": "libc0.1-dev"},
          {"reference": "libc0.1-dev-i386"},
          {"reference": "libc0.1-i386"},
          {"reference": "libc0.1-i686"},
          {"reference": "libc0.1-pic"},
          {"reference": "libc0.1-udeb"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-pic"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-armel"},
          {"reference": "libc6-armhf"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-armel"},
          {"reference": "libc6-dev-armhf"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-i686"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-pic"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6-xen"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-alphaev67"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-pic"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "multiarch-support"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-18.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "18.04",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.1"},
          {"reference": "libc0.1-dbg"},
          {"reference": "libc0.1-dev"},
          {"reference": "libc0.1-dev-i386"},
          {"reference": "libc0.1-i386"},
          {"reference": "libc0.1-pic"},
          {"reference": "libc0.1-udeb"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-pic"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc0.3-xen"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-armel"},
          {"reference": "libc6-armhf"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-armel"},
          {"reference": "libc6-dev-armhf"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-pic"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6-xen"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-alphaev67"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-pic"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "multiarch-support"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-20.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "20.04",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.1"},
          {"reference": "libc0.1-dbg"},
          {"reference": "libc0.1-dev"},
          {"reference": "libc0.1-dev-i386"},
          {"reference": "libc0.1-i386"},
          {"reference": "libc0.1-pic"},
          {"reference": "libc0.1-udeb"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-pic"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc0.3-xen"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-armel"},
          {"reference": "libc6-armhf"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-armel"},
          {"reference": "libc6-dev-armhf"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-lse"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-pic"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6-xen"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-alphaev67"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-pic"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-22.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "22.04",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-devtools"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.1"},
          {"reference": "libc0.1-dbg"},
          {"reference": "libc0.1-dev"},
          {"reference": "libc0.1-dev-i386"},
          {"reference": "libc0.1-i386"},
          {"reference": "libc0.1-udeb"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc0.3-xen"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-prof"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6-xen"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-alphaev67"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-24.04": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "24.04",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-devtools"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "nscd"}
        ]
      }
    ]
  },
  "Ubuntu Linux-25.10": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "25.10",
        "pkgs": [
          {"reference": "glibc-doc"},
          {"reference": "glibc-source"},
          {"reference": "libc-bin"},
          {"reference": "libc-dev-bin"},
          {"reference": "libc-devtools"},
          {"reference": "libc-l10n"},
          {"reference": "libc0.3"},
          {"reference": "libc0.3-dbg"},
          {"reference": "libc0.3-dev"},
          {"reference": "libc0.3-udeb"},
          {"reference": "libc6"},
          {"reference": "libc6-amd64"},
          {"reference": "libc6-dbg"},
          {"reference": "libc6-dev"},
          {"reference": "libc6-dev-amd64"},
          {"reference": "libc6-dev-i386"},
          {"reference": "libc6-dev-mips32"},
          {"reference": "libc6-dev-mips64"},
          {"reference": "libc6-dev-mipsn32"},
          {"reference": "libc6-dev-powerpc"},
          {"reference": "libc6-dev-ppc64"},
          {"reference": "libc6-dev-s390"},
          {"reference": "libc6-dev-sparc"},
          {"reference": "libc6-dev-sparc64"},
          {"reference": "libc6-dev-x32"},
          {"reference": "libc6-i386"},
          {"reference": "libc6-mips32"},
          {"reference": "libc6-mips64"},
          {"reference": "libc6-mipsn32"},
          {"reference": "libc6-powerpc"},
          {"reference": "libc6-ppc64"},
          {"reference": "libc6-s390"},
          {"reference": "libc6-sparc"},
          {"reference": "libc6-sparc64"},
          {"reference": "libc6-udeb"},
          {"reference": "libc6-x32"},
          {"reference": "libc6.1"},
          {"reference": "libc6.1-dbg"},
          {"reference": "libc6.1-dev"},
          {"reference": "libc6.1-udeb"},
          {"reference": "locales"},
          {"reference": "locales-all"},
          {"reference": "nscd"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}