Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : PyJWT vulnerabilities (USN-8823-1)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-8823-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(350973);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/29");

  script_cve_id(
    "CVE-2026-48522",
    "CVE-2026-48523",
    "CVE-2026-48524",
    "CVE-2026-48525",
    "CVE-2026-48526"
  );
  script_xref(name:"USN", value:"8823-1");

  script_name(english:"Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : PyJWT vulnerabilities (USN-8823-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that
are affected by multiple vulnerabilities as referenced in the USN-8823-1 advisory.

    It was discovered that PyJWT incorrectly handled certain URIs when using PyJWKClient. A remote attacker
    could possibly use this issue to perform server-side request forgery (SSRF) or expose sensitive local
    files. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48522)

    It was discovered that PyJWT incorrectly verified cryptographic signatures when decoding tokens with PyJWK
    keys. A remote attacker could possibly use this issue to bypass signature verification and forge valid
    JSON Web Tokens. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-48523)

    It was discovered that PyJWT incorrectly handled unknown key identifiers in PyJWKClient. A remote attacker
    could possibly use this issue to cause PyJWT to make excessive network requests, resulting in a denial of
    service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48524)

    It was discovered that PyJWT incorrectly handled payload decoding during detached JWS token verification.
    A remote attacker could possibly use this issue to cause PyJWT to consume excessive resources, resulting
    in a denial of service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48525)

    It was discovered that PyJWT incorrectly validated JSON Web Keys when decoding tokens with both HMAC and
    asymmetric algorithms enabled. A remote attacker could possibly use this issue to forge valid tokens,
    resulting in an authentication bypass. (CVE-2026-48526)

Tenable has extracted the preceding description block directly from the Ubuntu 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://ubuntu.com/security/notices/USN-8823-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected python-jwt and / or python3-jwt packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N");
  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:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-48526");

  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:"2026/05/28");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/25");
  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:"cpe:/o:canonical:ubuntu_linux:16.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:22.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:24.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:26.04:-:lts");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python-jwt");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:python3-jwt");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Ubuntu Local Security Checks");

  script_copyright(english:"Ubuntu Security Notice (C) 2026 Canonical, Inc. / NASL script (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release || '22.04' >< os_release || '24.04' >< os_release || '26.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 20.04 / 22.04 / 24.04 / 26.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '16.04', 'pkgname': 'python-jwt', 'pkgver': '1.3.0-1ubuntu0.1+esm2', 'cves': ['CVE-2026-48526']},
    {'osver': '16.04', 'pkgname': 'python3-jwt', 'pkgver': '1.3.0-1ubuntu0.1+esm2', 'cves': ['CVE-2026-48526']},
    {'osver': '18.04', 'pkgname': 'python-jwt', 'pkgver': '1.5.3+ds1-1ubuntu0.1+esm2', 'cves': ['CVE-2026-48526']},
    {'osver': '18.04', 'pkgname': 'python3-jwt', 'pkgver': '1.5.3+ds1-1ubuntu0.1+esm2', 'cves': ['CVE-2026-48526']},
    {'osver': '20.04', 'pkgname': 'python3-jwt', 'pkgver': '1.7.1-2ubuntu2.1+esm2', 'cves': ['CVE-2026-48526']},
    {'osver': '22.04', 'pkgname': 'python3-jwt', 'pkgver': '2.3.0-1ubuntu0.4', 'cves': ['CVE-2026-48522', 'CVE-2026-48526']},
    {'osver': '24.04', 'pkgname': 'python3-jwt', 'pkgver': '2.7.0-1ubuntu0.2', 'cves': ['CVE-2026-48522', 'CVE-2026-48524', 'CVE-2026-48525', 'CVE-2026-48526']},
    {'osver': '26.04', 'pkgname': 'python3-jwt', 'pkgver': '2.10.1-4ubuntu1.1', 'cves': ['CVE-2026-48522', 'CVE-2026-48523', 'CVE-2026-48524', 'CVE-2026-48525', 'CVE-2026-48526']}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (osver && pkgname && pkgver) {
    if (deb_check(release:osver, prefix:pkgname, reference:pkgver, cves:cves)) flag++;
  }
}

if (flag)
{
  var extra = '';
  extra += ubuntu_report_get();
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : extra
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'python-jwt / python3-jwt');
}