Amazon Linux 2023 : nginx, nginx-all-modules, nginx-core (ALAS2023-2026-1922)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2026-1922.
##

include('compat.inc');

if (description)
{
  script_id(327392);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/16");

  script_cve_id("CVE-2026-42055", "CVE-2026-48142");
  script_xref(name:"IAVA", value:"2026-A-0601");

  script_name(english:"Amazon Linux 2023 : nginx, nginx-all-modules, nginx-core (ALAS2023-2026-1922)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1922 advisory.

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and
    ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass
    directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the
    large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker,
    along with conditions beyond their control, could send large headers while creating an upstream request.
    This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart.
    Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR)
    disabled or when the attacker can bypass ASLR.

    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-42055)

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module. When content
    is served or proxied through a location block with both source_charset utf-8; and a charset directive (for
    example, charset koi8-r;) configured, remote, unauthenticated attackers can send requests (in conjunction
    with conditions beyond their control) to cause a heap buffer over-read in the NGINX worker process,
    leading to limited disclosure of memory or a restart.

    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-48142)

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//AL2023/ALAS2023-2026-1922.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-2026-42055.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-48142.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update nginx --releasever 2023.12.20260706' or
  or 'dnf update --advisory ALAS2023-2026-1922 --releasever 2023.12.20260706' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/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:H/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:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/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-2026-42055");

  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:"2026/06/17");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-all-modules");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-core");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-core-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-filesystem");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-image-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-image-filter-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-perl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-perl-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-xslt-filter");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-http-xslt-filter-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-mail");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-mail-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-stream");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-stream-debuginfo");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  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 != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

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

var pkgs = [
    {'reference':'nginx-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-all-modules-1.30.3-1.amzn2023.0.1', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-core-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-core-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-core-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-core-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-debugsource-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-debugsource-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-filesystem-1.30.3-1.amzn2023.0.1', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-devel-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-devel-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-image-filter-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-image-filter-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-image-filter-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-image-filter-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-perl-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-perl-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-perl-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-perl-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-xslt-filter-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-xslt-filter-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-xslt-filter-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-http-xslt-filter-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-mail-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-mail-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-mail-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-mail-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-stream-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-stream-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-stream-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'nginx-mod-stream-debuginfo-1.30.3-1.amzn2023.0.1', 'cpu':'x86_64', 'release':'AL-2023', '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, "nginx / nginx-all-modules / nginx-core / etc");
}