Debian dla-4831 : libgit2-1.5 - security update

#%NASL_MIN_LEVEL 80900
#
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Debian Security Advisory dla-4831. The text
# itself is copyright (C) Software in the Public Interest, Inc.
#

include('compat.inc');

if (description)
{
  script_id(370004);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/21");

  script_cve_id(
    "CVE-2026-5917",
    "CVE-2026-53584",
    "CVE-2026-53585",
    "CVE-2026-53586"
  );

  script_name(english:"Debian dla-4831 : libgit2-1.5 - 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 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the
dla-4831 advisory.

    - -------------------------------------------------------------------------
    Debian LTS Advisory DLA-4831-1                [email protected]
    https://www.debian.org/lts/security/                        Simon Quigley
    October 12, 2026                              https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : libgit2
    Version        : 1.5.1+ds-1+deb12u2
    CVE ID         : CVE-2026-5917 CVE-2026-53584 CVE-2026-53585 CVE-2026-53586
    Debian Bug     : 1144465

    Multiple security issues were discovered in libgit2, a low-level Git
    library, which could result in path traversal, denial of service,
    credential leaks, or the execution of arbitrary commands on an SSH
    server.

    CVE-2026-5917

        The repository path was placed unescaped inside single quotes in
        the command sent to the server over SSH, so a path containing a
        single quote could execute arbitrary commands on the SSH server.
        The path is now escaped.

    CVE-2026-53584

        Submodule paths read from .gitmodules were not checked for ..,
        so a malicious repository could make submodule lookup, add, init
        or update operate outside the working tree. Such paths are now
        rejected.

    CVE-2026-53585

        Delta application allocated whatever result size the delta header
        declared, so a small malicious packfile could force huge memory
        allocations, leading to a denial of service. Objects produced by
        delta application are now limited to 2 GiB by default; the limit
        can be changed with GIT_OPT_SET_PACK_MAX_OBJECT_SIZE.

    CVE-2026-53586

        After an offsite redirect on the initial HTTP request, the
        credential callback was still given the original URL, so a
        credential helper could hand the credentials for the original host
        to the redirect target. The callback now receives the host that is
        actually being contacted.

    For Debian 12 bookworm, these problems have been fixed in version
    1.5.1+ds-1+deb12u2.

    We recommend that you upgrade your libgit2 packages.

    For the detailed security status of libgit2 please refer to
    its security tracker page at:
    https://security-tracker.debian.org/tracker/libgit2

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

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/libgit2");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-53584");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-53585");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-53586");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-5917");
  script_set_attribute(attribute:"see_also", value:"https://packages.debian.org/source/bookworm/libgit2");
  script_set_attribute(attribute:"solution", value:
"Upgrade the libgit2-1.5 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:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N");
  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:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-5917");
  script_set_attribute(attribute:"cvss3_score_source", value:"CVE-2026-53586");

  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:"2026/07/23");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/21");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libgit2-1.5");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libgit2-dev");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:libgit2-fixtures");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  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_info2.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:"^(12)\.[0-9]+", string:debian_release)) audit(AUDIT_OS_NOT, 'Debian 12.0', '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': '12.0', 'prefix': 'libgit2-1.5', 'reference': '1.5.1+ds-1+deb12u2'},
    {'release': '12.0', 'prefix': 'libgit2-dev', 'reference': '1.5.1+ds-1+deb12u2'},
    {'release': '12.0', 'prefix': 'libgit2-fixtures', 'reference': '1.5.1+ds-1+deb12u2'}
];

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, 'libgit2-1.5 / libgit2-dev / libgit2-fixtures');
}