Amazon Linux 2023 : cjose, cjose-devel (ALAS2023-2026-3130)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2026-3130.
##

include('compat.inc');

if (description)
{
  script_id(351025);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/29");

  script_cve_id("CVE-2026-53938", "CVE-2026-53939");

  script_name(english:"Amazon Linux 2023 : cjose, cjose-devel (ALAS2023-2026-3130)");

  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 ALAS2023-2026-3130 advisory.

    OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). Prior to
    version 0.6.2.5, cjose's JWE decryption path for the AES Key Wrap key-management algorithms (`alg` =
    `A128KW`, `A192KW`, `A256KW`) does not validate the length of the attacker-supplied `encrypted_key` (JWE
    Encrypted Key) before unwrapping it into a fixed-size, heap-allocated Content Encryption Key (CEK) buffer.
    A remote, unauthenticated attacker who can submit a crafted JWE to an application that decrypts it with an
    AES-KW symmetric key can trigger an out-of-bounds heap write, corrupting the heap. This leads at minimum
    to a crash (denial of service) and, depending on the heap layout and allocator, may be leverageable for
    further memory-corruption impact. `cjose_jwe_import()` / `cjose_jwe_decrypt()` are pre-authentication
    entry points: they parse and process fully attacker-controlled input. Upgrade to cjose 0.6.2.5 to receive
    a patch. If upgrading is not immediately possible, reject the AES Key Wrap algorithms
    (`A128KW`/`A192KW`/`A256KW`) for untrusted JWEs at the application layer. (CVE-2026-53938)

    OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). In versions
    0.6.1 through 0.6.2.5, when cjose encrypts a JWE using an AES-CBC-HMAC content-encryption algorithm
    (`A128CBC-HS256`, `A192CBC-HS384`, or `A256CBC-HS512`) together with any key-management algorithm that
    generates a fresh content-encryption key (CEK), the CEK is all zero bytes instead of being randomly
    generated. The resulting JWE is therefore encrypted and authenticated under a fixed, publicly known key,
    so anyone who obtains the JWE can recover the plaintext and forge or modify the content. This is fixed in
    version 0.6.2.6 by `_cjose_jwe_set_cek_aes_cbc()` generating the CEK from `RAND_bytes`. A regression test
    asserts that the `encrypted_key` differs across two encryptions for each AES-CBC-HMAC variant. Until
    upgrading, for data encrypted with cjose, three options are available. Use an AES-GCM `enc` (`A128GCM` /
    `A192GCM` / `A256GCM`) instead of an AES-CBC-HMAC `enc`,  use `alg=dir` with a caller-supplied CEK, or
    avoid using cjose for JWE encryption with the affected algorithm pair. These are mitigations for new
    ciphertexts only; data already encrypted under the zero key remains compromised and should be re-encrypted
    (and any secrets it contained rotated). (CVE-2026-53939)

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/ALAS2023-2026-3130.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-2026-53938.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2026-53939.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update cjose --releasever 2023.12.20260928' or
  or 'dnf update --advisory ALAS2023-2026-3130 --releasever 2023.12.20260928' 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:L/PR:N/UI:N/S:U/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-2026-53939");

  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:"2026/09/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/29");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:cjose");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:cjose-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:cjose-debugsource");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:cjose-devel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  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':'cjose-0.6.2.2-7.amzn2023', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-0.6.2.2-7.amzn2023', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-debuginfo-0.6.2.2-7.amzn2023', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-debuginfo-0.6.2.2-7.amzn2023', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-debugsource-0.6.2.2-7.amzn2023', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-debugsource-0.6.2.2-7.amzn2023', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-devel-0.6.2.2-7.amzn2023', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'cjose-devel-0.6.2.2-7.amzn2023', '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, "cjose / cjose-debuginfo / cjose-debugsource / etc");
}