Amazon Linux 2 : gstreamer-plugins-bad-free, --advisory ALAS2-2026-3791 (ALAS-2026-3791)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2026-3791.
##

include('compat.inc');

if (description)
{
  script_id(325566);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/08");

  script_cve_id("CVE-2026-52720", "CVE-2026-52721", "CVE-2026-52722");

  script_name(english:"Amazon Linux 2 : gstreamer-plugins-bad-free, --advisory ALAS2-2026-3791 (ALAS-2026-3791)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of gstreamer-plugins-bad-free installed on the remote host is prior to 0.10.23-42. It is, therefore,
affected by multiple vulnerabilities as referenced in the ALAS2-2026-3791 advisory.

    A heap buffer overflow vulnerability was found in GStreamer's librfb (RFB/VNC client). The rectangle
    bounds check incorrectly validates area rather than individual dimensions, allowing a malicious VNC server
    to send a rectangle that extends beyond the framebuffer. A remote attacker could set up a malicious VNC
    server and trick a user into connecting, resulting in an out-of-bounds heap write that could lead to code
    execution or a crash. (CVE-2026-52720)

    Multiple out-of-bounds read vulnerabilities were found in GStreamer's pcapparse element. Malformed PCAP
    records can trigger reads beyond buffer boundaries during IPv4/TCP header parsing. This element is
    primarily used in debugging pipelines, limiting real-world exposure. A local attacker could trick a user
    into processing a specially crafted PCAP file, potentially leading to a crash or information disclosure.
    (CVE-2026-52721)

    A signed integer overflow vulnerability was found in GStreamer's VMnc decoder. A crafted VMnc stream with
    large cursor dimensions can overflow signed integer payload-size arithmetic, bypassing a length check and
    leading to out-of-bounds reads. A remote attacker could trick a user into opening a specially crafted VMnc
    file, potentially causing a crash or information disclosure. (CVE-2026-52722)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com//AL2/ALAS2-2026-3791.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-52720.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-52721.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-52722.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update gstreamer-plugins-bad-free' or
  or 'yum update --advisory ALAS2-2026-3791' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:H/Au:N/C:P/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-52721");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-52720");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/08");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gstreamer-plugins-bad-free");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gstreamer-plugins-bad-free-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gstreamer-plugins-bad-free-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gstreamer-plugins-bad-free-devel-docs");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon Linux Local Security Checks");

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

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}

include("rpm2.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'gstreamer-plugins-bad-free-0.10.23-42.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-0.10.23-42.amzn2.0.4', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-0.10.23-42.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-debuginfo-0.10.23-42.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-debuginfo-0.10.23-42.amzn2.0.4', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-debuginfo-0.10.23-42.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-0.10.23-42.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-0.10.23-42.amzn2.0.4', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-0.10.23-42.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-docs-0.10.23-42.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-docs-0.10.23-42.amzn2.0.4', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gstreamer-plugins-bad-free-devel-docs-0.10.23-42.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "gstreamer-plugins-bad-free / gstreamer-plugins-bad-free-debuginfo / gstreamer-plugins-bad-free-devel / etc");
}