Amazon Linux 2023 : runfinch-finch (ALAS2023-2026-2023)

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

include('compat.inc');

if (description)
{
  script_id(332009);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/04");

  script_cve_id(
    "CVE-2026-39822",
    "CVE-2026-42505",
    "CVE-2026-48702",
    "CVE-2026-49478",
    "CVE-2026-49835"
  );
  script_xref(name:"IAVB", value:"2026-B-0193");

  script_name(english:"Amazon Linux 2023 : runfinch-finch (ALAS2023-2026-2023)");

  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 ALAS2023-2026-2023 advisory.

    On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root
    when the final path component of the a path is a symbolic link and the path ends in /. For example,
    'root.Open(symlink/)' will open symlink even when symlink is a symbolic link pointing outside of the
    root. (CVE-2026-39822)

    Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a
    disclosure of pre-shared key identities in the unencrypted client hello. (CVE-2026-42505)

    A flaw was found in Rekor. The `Package.Unmarshal()` function, which processes Alpine Package Keep (APK)
    files, decompresses gzip streams without limiting the total decompressed size. A remote attacker can
    exploit this by crafting a malicious APK file with a high compression ratio, causing the server to consume
    excessive memory. This leads to a Denial of Service (DoS) through an out-of-memory (OOM) error, and can be
    triggered via unauthenticated API endpoints. (CVE-2026-48702)

    A flaw was found in Fulcio's OpenID Connect (OIDC) Discovery client. This vulnerability allows a remote
    attacker to perform Server-Side Request Forgery (SSRF) by redirecting discovery requests to internal
    systems. Additionally, an attacker can manipulate the JSON Web Key Set (JWKS) Uniform Resource Identifier
    (URI) to poison the verifier cache with malicious keys, enabling the validation of attacker-controlled
    signatures. Furthermore, the flaw can lead to the leakage of Kubernetes ServiceAccount tokens to third-
    party hosts through cross-host redirects or misconfigured MetaIssuers, potentially exposing sensitive
    cluster credentials. (CVE-2026-49478)

    A flaw was found in Sigstore Timestamp Authority. An unauthenticated remote attacker can exploit this
    vulnerability by sending requests with arbitrary HTTP paths and methods. This leads to the creation of an
    excessive number of unique metric labels, causing unbounded memory growth and a denial of service (DoS)
    condition on the server. This issue is a type of Improper Restriction of Resource Consumption (CWE-770).
    (CVE-2026-49835)

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/ALAS2023-2026-2023.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-2026-39822.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-42505.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-48702.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-49478.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-49835.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update runfinch-finch --releasever 2023.12.20260803' or
  or 'dnf update --advisory ALAS2023-2026-2023 --releasever 2023.12.20260803' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/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:N/S:U/C:N/I:N/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-2026-49835");

  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:"2026/06/25");
  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:runfinch-finch");
  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':'runfinch-finch-1.17.2-1.amzn2023.0.3', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'runfinch-finch-1.17.2-1.amzn2023.0.3', '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, "runfinch-finch");
}