Amazon Linux 2 : nginx, --advisory ALAS2NGINX1-2026-015 (ALASNGINX1-2026-015)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALASNGINX1-2026-015.
##

include('compat.inc');

if (description)
{
  script_id(332006);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/04");

  script_cve_id("CVE-2026-42533", "CVE-2026-56434", "CVE-2026-60005");
  script_xref(name:"IAVA", value:"2026-A-0754");

  script_name(english:"Amazon Linux 2 : nginx, --advisory ALAS2NGINX1-2026-015 (ALASNGINX1-2026-015)");

  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 nginx installed on the remote host is prior to 1.30.4-1. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2NGINX1-2026-015 advisory.

    A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a
    string expression references the map's regex capture variables before referencing the map output variable.
    Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression
    under certain conditions. An unauthenticated attacker along with conditions beyond their control can
    exploit this vulnerability by sending crafted HTTP requests. This may cause a heap 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.

    Impact:This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX
    system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane
    issue only.



    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-42533)

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssi_module module. This
    vulnerability may exist when the Server-Side Includes (SSI), proxy_pass, and proxy_buffering off
    directives are configured. With this configuration, an unauthenticated attacker with man-in-the-middle
    (MITM) ability to control responses from an upstream server may be able to cause a use-after-free in the
    NGINX worker process. This issue may lead to limited modification of memory or a restart of the NGINX
    worker process.

    Impact:This vulnerability may allow remote attackers to have limited control to modify memory contents or
    restart the NGINX worker process. There is no control plane exposure; this is a data plane issue only.

    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-56434)

    NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_slice_module module. When the slice
    directive and unnamed regex captures are configured or when a background cache update happens,
    unauthenticated attackers can send requests that may cause uninitialized memory access in the NGINX worker
    process, leading to limited disclosure of memory or a restart.

    Impact:This vulnerability may allow remote, unauthenticated attackers to have limited control to disclose
    memory contents or restart the NGINX worker process. There is no control plane exposure; this is a data
    plane issue only.Note: The ngx_http_slice_module module is not enabled by default; it's enabled with the
    --with-http_slice_module configuration parameter.

    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2026-60005)

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/ALAS2NGINX1-2026-015.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-2026-42533.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-56434.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-60005.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update nginx' or
  or 'yum update --advisory ALAS2NGINX1-2026-015' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:H/AT:N/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:P");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-60005");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-42533");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-42533");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/07/15");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/04");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/04");

  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-debuginfo");
  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-geoip");
  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-perl");
  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-mail");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:nginx-mod-stream");
  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-nginx1"';
if (REPOS_FOUND && (repository >!< extras_list)) exit(0, AFFECTED_REPO_NOT_ENABLED);

var pkgs = [
    {'reference':'nginx-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-all-modules-1.30.4-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-core-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-core-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-debuginfo-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-debuginfo-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-filesystem-1.30.4-1.amzn2.0.1', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-devel-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-devel-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-geoip-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-geoip-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-image-filter-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-image-filter-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-perl-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-perl-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-xslt-filter-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-http-xslt-filter-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-mail-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-mail-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-stream-1.30.4-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'},
    {'reference':'nginx-mod-stream-1.30.4-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'nginx1'}
];

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, "nginx / nginx-all-modules / nginx-core / etc");
}