Amazon Linux 2 : containerd, --advisory ALAS2ECS-2026-132 (ALASECS-2026-132)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALASECS-2026-132.
##

include('compat.inc');

if (description)
{
  script_id(328476);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/20");

  script_cve_id(
    "CVE-2026-25680",
    "CVE-2026-25681",
    "CVE-2026-27136",
    "CVE-2026-39821",
    "CVE-2026-42502",
    "CVE-2026-42506"
  );
  script_xref(name:"IAVB", value:"2026-B-0120");

  script_name(english:"Amazon Linux 2 : containerd, --advisory ALAS2ECS-2026-132 (ALASECS-2026-132)");

  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 containerd installed on the remote host is prior to 2.1.7-1. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2ECS-2026-132 advisory.

    Parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.
    (CVE-2026-25680)

    Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can
    be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
    (CVE-2026-25681)

    Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can
    be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
    (CVE-2026-27136)

    The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-
    only label. For example, ToUnicode(xn--example-.com) incorrectly returns the name example.com rather
    than an error. This behavior can lead to privilege escalation in programs using the idna package. For
    example, a program which performs privilege checks on the ASCII hostname may reject example.com but
    permit xn--example-.com. If that program subsequently converts the ASCII hostname to Unicode, it will
    inadvertently permits access to the Unicode name example.com. (CVE-2026-39821)

    Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can
    be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
    (CVE-2026-42502)

    Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can
    be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
    (CVE-2026-42506)

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/ALAS2ECS-2026-132.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-2026-25680.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-25681.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-27136.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-39821.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-42502.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-42506.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update containerd' or
  or 'yum update --advisory ALAS2ECS-2026-132' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-39821");

  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:"2026/05/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/20");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:containerd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:containerd-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:containerd-stress");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  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 REPOS_FOUND = TRUE;
var extras_list = get_kb_item("Host/AmazonLinux/extras_label_list");
if (isnull(extras_list)) REPOS_FOUND = FALSE;
var repository = '"amzn2extra-ecs"';
if (REPOS_FOUND && (repository >!< extras_list)) exit(0, AFFECTED_REPO_NOT_ENABLED);

var pkgs = [
    {'reference':'containerd-2.1.7-1.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'containerd-2.1.7-1.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'containerd-debuginfo-2.1.7-1.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'containerd-debuginfo-2.1.7-1.amzn2.0.4', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'containerd-stress-2.1.7-1.amzn2.0.4', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'containerd-stress-2.1.7-1.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)
{
  var extra = rpm_report_get();
  if (!REPOS_FOUND) extra = rpm_report_get() + report_repo_caveat();
  security_report_v4(
      port       : 0,
      severity   : SECURITY_HOLE,
      extra      : extra
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "containerd / containerd-debuginfo / containerd-stress");
}