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Linux Distros Unpatched Vulnerability : CVE-2026-27145

🗓️ 03 Jun 2026 00:00:00Reported by TenableType 
nessus
 nessus
🔗 www.tenable.com👁 2 Views

Linux hosts with unpatched vulnerability CVE-2026-27145 cause quadratic hostname verification.

Related
Refs
Code
ReporterTitlePublishedViews
Family
ATTACKERKB
CVE-2026-27145
2 Jun 202622:01
attackerkb
Circl
CVE-2026-27145
3 Jun 202612:00
circl
CVE
CVE-2026-27145
2 Jun 202622:01
cve
Cvelist
CVE-2026-27145 Inefficient candidate hostname parsing in crypto/x509
2 Jun 202622:01
cvelist
Debian CVE
CVE-2026-27145
2 Jun 202622:01
debiancve
EUVD
EUVD-2026-34038
3 Jun 202600:30
euvd
NVD
CVE-2026-27145
2 Jun 202623:16
nvd
OSV
DEBIAN-CVE-2026-27145
2 Jun 202623:16
osv
OSV
GO-2026-5037 Inefficient candidate hostname parsing in crypto/x509
2 Jun 202621:39
osv
OSV
UBUNTU-CVE-2026-27145
3 Jun 202600:00
osv
Rows per page
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(318379);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/03");

  script_cve_id("CVE-2026-27145");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-27145");

  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.

  - (*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject
    Alternative Name (SAN) entries. This caused strings.Split(host, .) to execute repeatedly on the same
    input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of
    SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before
    building the certificate chain, this overhead occurred even for untrusted certificates. (CVE-2026-27145)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27145");
  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:N/I:P/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-27145");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_unpatched", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/03");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-1.15");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-1.19");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-1.24");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-1.25");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:golang-1.26");
  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/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14");

  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 = {
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "golang-1.15"},
          {"reference": "golang-1.15-doc"},
          {"reference": "golang-1.15-go"},
          {"reference": "golang-1.15-src"}
        ]
      }
    ]
  },
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "golang-1.19"},
          {"reference": "golang-1.19-doc"},
          {"reference": "golang-1.19-go"},
          {"reference": "golang-1.19-src"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "golang-1.24"},
          {"reference": "golang-1.24-doc"},
          {"reference": "golang-1.24-go"},
          {"reference": "golang-1.24-src"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "golang-1.25"},
          {"reference": "golang-1.25-doc"},
          {"reference": "golang-1.25-go"},
          {"reference": "golang-1.25-src"},
          {"reference": "golang-1.26"},
          {"reference": "golang-1.26-doc"},
          {"reference": "golang-1.26-go"},
          {"reference": "golang-1.26-src"}
        ]
      }
    ]
  }
};

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_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}

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03 Jun 2026 00:00Current
5.9Medium risk
Vulners AI Score5.9
EPSS0.00004
2