Linux Distros Unpatched Vulnerability : CVE-2026-66038

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

include('compat.inc');

if (description)
{
  script_id(329734);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/25");

  script_cve_id("CVE-2026-66038");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-66038");

  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.

  - FFmpeg through 8.1.2, fixed in commit 8670835, contains an information disclosure vulnerability in the
    LCL/ZLIB video decoder that allows attackers to expose uninitialized heap memory by supplying a valid zlib
    stream that inflates to fewer bytes than the expected frame size. The zlib_decomp() function in lcldec.c
    treats short decompression as non-fatal and continues to the RGB24 conversion path, which copies a full
    frame's worth of rows from the allocation buffer using original frame dimensions, causing uninitialized
    heap contents including pointer-derived allocator bytes to be copied into the attacker-observable AVFrame
    output and potentially defeating ASLR in long-lived media processing services. (CVE-2026-66038)

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-2026-66038");
  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:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-66038");

  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:"2026/07/24");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/25");

  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:ffmpeg");
  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-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "ffmpeg"},
          {"reference": "ffmpeg-doc"},
          {"reference": "libavcodec-dev"},
          {"reference": "libavcodec-extra"},
          {"reference": "libavcodec-extra59"},
          {"reference": "libavcodec59"},
          {"reference": "libavdevice-dev"},
          {"reference": "libavdevice59"},
          {"reference": "libavfilter-dev"},
          {"reference": "libavfilter-extra"},
          {"reference": "libavfilter-extra8"},
          {"reference": "libavfilter8"},
          {"reference": "libavformat-dev"},
          {"reference": "libavformat-extra"},
          {"reference": "libavformat-extra59"},
          {"reference": "libavformat59"},
          {"reference": "libavutil-dev"},
          {"reference": "libavutil57"},
          {"reference": "libpostproc-dev"},
          {"reference": "libpostproc56"},
          {"reference": "libswresample-dev"},
          {"reference": "libswresample4"},
          {"reference": "libswscale-dev"},
          {"reference": "libswscale6"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "ffmpeg"},
          {"reference": "ffmpeg-doc"},
          {"reference": "libavcodec-dev"},
          {"reference": "libavcodec-extra"},
          {"reference": "libavcodec-extra58"},
          {"reference": "libavcodec58"},
          {"reference": "libavdevice-dev"},
          {"reference": "libavdevice58"},
          {"reference": "libavfilter-dev"},
          {"reference": "libavfilter-extra"},
          {"reference": "libavfilter-extra7"},
          {"reference": "libavfilter7"},
          {"reference": "libavformat-dev"},
          {"reference": "libavformat58"},
          {"reference": "libavresample-dev"},
          {"reference": "libavresample4"},
          {"reference": "libavutil-dev"},
          {"reference": "libavutil56"},
          {"reference": "libpostproc-dev"},
          {"reference": "libpostproc55"},
          {"reference": "libswresample-dev"},
          {"reference": "libswresample3"},
          {"reference": "libswscale-dev"},
          {"reference": "libswscale5"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "ffmpeg"},
          {"reference": "ffmpeg-doc"},
          {"reference": "libavcodec-dev"},
          {"reference": "libavcodec-extra"},
          {"reference": "libavcodec-extra62"},
          {"reference": "libavcodec62"},
          {"reference": "libavdevice-dev"},
          {"reference": "libavdevice62"},
          {"reference": "libavfilter-dev"},
          {"reference": "libavfilter-extra"},
          {"reference": "libavfilter-extra11"},
          {"reference": "libavfilter11"},
          {"reference": "libavformat-dev"},
          {"reference": "libavformat-extra"},
          {"reference": "libavformat-extra62"},
          {"reference": "libavformat62"},
          {"reference": "libavutil-dev"},
          {"reference": "libavutil60"},
          {"reference": "libswresample-dev"},
          {"reference": "libswresample6"},
          {"reference": "libswscale-dev"},
          {"reference": "libswscale9"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "ffmpeg"},
          {"reference": "ffmpeg-doc"},
          {"reference": "libavcodec-dev"},
          {"reference": "libavcodec-extra"},
          {"reference": "libavcodec-extra61"},
          {"reference": "libavcodec61"},
          {"reference": "libavdevice-dev"},
          {"reference": "libavdevice61"},
          {"reference": "libavfilter-dev"},
          {"reference": "libavfilter-extra"},
          {"reference": "libavfilter-extra10"},
          {"reference": "libavfilter10"},
          {"reference": "libavformat-dev"},
          {"reference": "libavformat-extra"},
          {"reference": "libavformat-extra61"},
          {"reference": "libavformat61"},
          {"reference": "libavutil-dev"},
          {"reference": "libavutil59"},
          {"reference": "libpostproc-dev"},
          {"reference": "libpostproc58"},
          {"reference": "libswresample-dev"},
          {"reference": "libswresample5"},
          {"reference": "libswscale-dev"},
          {"reference": "libswscale8"}
        ]
      }
    ]
  }
};

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 third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

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');
}