Debian dsa-6493 : libevent-2.1-7t64 - 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-6493. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(344780);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/11");

  script_cve_id(
    "CVE-2026-63379",
    "CVE-2026-63381",
    "CVE-2026-63382",
    "CVE-2026-63383",
    "CVE-2026-63384",
    "CVE-2026-63385",
    "CVE-2026-63387",
    "CVE-2026-63388"
  );

  script_name(english:"Debian dsa-6493 : libevent-2.1-7t64 - 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 packages installed that are affected by multiple vulnerabilities as referenced in the
dsa-6493 advisory.

    - -------------------------------------------------------------------------
    Debian Security Advisory DSA-6493-1                   [email protected]
    https://www.debian.org/security/                                  Aron Xu
    September 11, 2026                    https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : libevent
    CVE ID         : CVE-2026-63379 CVE-2026-63381 CVE-2026-63382 CVE-2026-63383
                     CVE-2026-63384 CVE-2026-63385 CVE-2026-63387 CVE-2026-63388

    Several vulnerabilities were discovered in libevent, an asynchronous event
    notification library.

    The HTTP implementation (evhttp) handled Transfer-Encoding and
    Content-Length headers, chunked-encoding line terminators, header line
    folding and chunked trailers too permissively, which could allow HTTP
    request smuggling, header injection or access control bypass when a
    libevent-based server or client is combined with an HTTP proxy.

    Out-of-bounds memory accesses in the DNS (evdns), tagged RPC
    (evtag/evrpc) and buffered socket (bufferevent) code, and a
    use-after-free in evbuffer, could result in denial of service or
    potentially the execution of arbitrary code when processing untrusted
    input.

    For the stable distribution (trixie), these problems have been fixed in
    version 2.1.13-stable-1~deb13u1.

    We recommend that you upgrade your libevent packages.

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

    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/libevent");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63379");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63381");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63382");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63383");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63384");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63385");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63387");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-63388");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/trixie/libevent");
  script_set_attribute(attribute:"solution", value:
"Upgrade the libevent-2.1-7t64 packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-63388");
  script_set_attribute(attribute:"cvss4_score_source", value:"CVE-2026-63385");

  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:"2026/08/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-2.1-7t64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-core-2.1-7t64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-extra-2.1-7t64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-openssl-2.1-7t64");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libevent-pthreads-2.1-7t64");
  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': 'libevent-2.1-7t64', 'reference': '2.1.13-stable-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libevent-core-2.1-7t64', 'reference': '2.1.13-stable-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libevent-dev', 'reference': '2.1.13-stable-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libevent-extra-2.1-7t64', 'reference': '2.1.13-stable-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libevent-openssl-2.1-7t64', 'reference': '2.1.13-stable-1~deb13u1'},
    {'release': '13.0', 'prefix': 'libevent-pthreads-2.1-7t64', 'reference': '2.1.13-stable-1~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, 'libevent-2.1-7t64 / libevent-core-2.1-7t64 / libevent-dev / etc');
}