Amazon Linux 2 : golang, --advisory ALAS2-2026-3893 (ALAS-2026-3893)

#%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-2026-3893.
##

include('compat.inc');

if (description)
{
  script_id(341867);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/31");

  script_cve_id(
    "CVE-2026-33818",
    "CVE-2026-56853",
    "CVE-2026-56858",
    "CVE-2026-56859",
    "CVE-2026-56860",
    "CVE-2026-56862",
    "CVE-2026-56864",
    "CVE-2026-56865"
  );
  script_xref(name:"IAVB", value:"2026-B-0234");

  script_name(english:"Amazon Linux 2 : golang, --advisory ALAS2-2026-3893 (ALAS-2026-3893)");

  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 golang installed on the remote host is prior to 1.26.7-1. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2-2026-3893 advisory.

    Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive
    structures. (CVE-2026-33818)

    When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection
    to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when
    doing this. (CVE-2026-56853)

    Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to
    inject arbitrary content, potentially leading to XSS. (CVE-2026-56858)

    Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack
    exhaustion. (CVE-2026-56859)

    Previously, resolving relative paths containing parent directory ('..') segments performed string
    conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory
    allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for
    '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.
    (CVE-2026-56860)

    Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a
    handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages
    to force the server to keep performing key derivation operations indefinitely. (CVE-2026-56862)

    A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency
    log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content
    that cannot be detected by evaluating the transparency log. In order to determine if you have been
    affected:   rm -r go.sum go.work.sum vendor/ && go mod tidy (CVE-2026-56864)

    A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested
    module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module
    cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be
    detected by evaluating the transparency log. All tiles are now correctly verified against their parents.
    In order to determine if you have been affected:   rm -r go.sum go.work.sum vendor/ && go mod tidy
    (CVE-2026-56865)

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/ALAS2-2026-3893.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-2026-33818.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56853.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56858.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56859.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56860.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56862.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56864.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56865.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update golang' or
  or 'yum update --advisory ALAS2-2026-3893' 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:L/AC:L/PR:N/UI:N/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-2026-56858");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-56865");

  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:"2026/08/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/31");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/31");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-bin");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-docs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-misc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-shared");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-src");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:golang-tests");
  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 pkgs = [
    {'reference':'golang-1.26.7-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-1.26.7-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-bin-1.26.7-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-bin-1.26.7-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-docs-1.26.7-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-misc-1.26.7-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-shared-1.26.7-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-shared-1.26.7-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-src-1.26.7-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'golang-tests-1.26.7-1.amzn2.0.1', '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_HOLE,
      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, "golang / golang-bin / golang-docs / etc");
}