Debian dsa-6429 : caddy - security update

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory dsa-6429. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(334443);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/11");

  script_cve_id(
    "CVE-2026-27585",
    "CVE-2026-27587",
    "CVE-2026-27588",
    "CVE-2026-27589",
    "CVE-2026-27590",
    "CVE-2026-45692",
    "CVE-2026-52845",
    "CVE-2026-52846"
  );

  script_name(english:"Debian dsa-6429 : caddy - security update");

  script_set_attribute(attribute:"synopsis", value:
"The remote Debian host is missing one or more security-related updates.");
  script_set_attribute(attribute:"description", value:
"The remote Debian 13 host has a package installed that is affected by multiple vulnerabilities as referenced in the
dsa-6429 advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6429-1                   [email protected]
    https://www.debian.org/security/                                  Aron Xu
    August 11, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : caddy
    CVE ID         : CVE-2026-27585 CVE-2026-27587 CVE-2026-27588 CVE-2026-27589
                     CVE-2026-27590 CVE-2026-45692 CVE-2026-52845 CVE-2026-52846

    Multiple security issues were discovered in Caddy, a web server with
    automatic HTTPS, which may result in the bypass of path- or host-based
    access controls, the execution of an unintended file by a FastCGI
    backend, the injection of identity headers trusted by applications
    running behind Caddy, unauthorised reconfiguration of the server through
    its admin API, or cross-site scripting.

    The fix for CVE-2026-52845 follows upstream in dropping every request
    header whose name contains an underscore, for all servers and without an
    opt-out. Deployments which pass such headers through Caddy, for instance
    X_Api_Key or gRPC custom metadata keys containing underscores, need to
    switch to the hyphenated spelling.

    For the stable distribution (trixie), these problems have been fixed in
    version 2.6.2-12+deb13u1.

    We recommend that you upgrade your caddy packages.

    For the detailed security status of caddy please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/caddy

    Further information about Debian Security Advisories, how to apply
    these updates to your system and frequently asked questions can be
    found at: https://www.debian.org/security/

    Mailing list: [email protected]

Tenable has extracted the preceding description block directly from the Debian 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://security-tracker.debian.org/tracker/source-package/caddy");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27585");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27587");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27588");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27589");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-27590");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-45692");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-52845");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-52846");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/trixie/caddy");
  script_set_attribute(attribute:"solution", value:
"Upgrade the caddy packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/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:L/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:L/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-2026-27590");

  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:"2026/02/24");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:caddy");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Debian 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/Debian/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);
if (!get_kb_item("Host/Debian/dpkg-l")) audit(AUDIT_PACKAGE_LIST_MISSING);

var debian_release = get_kb_item('Host/Debian/release');
if ( isnull(debian_release) ) audit(AUDIT_OS_NOT, 'Debian');
debian_release = chomp(debian_release);
if (! preg(pattern:"^(13)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 13.0', 'Debian ' + debian_release);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Debian', cpu);

var pkgs = [
    {'release': '13.0', 'prefix': 'caddy', 'reference': '2.6.2-12+deb13u1'}
];

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

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : deb_report_get()
  );
  exit(0);
}
else
{
  var tested = deb_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'caddy');
}