Amazon Linux 2 : gvfs (ALAS-2026-3943)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALAS-2026-3943.
##

include('compat.inc');

if (description)
{
  script_id(351080);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/29");

  script_cve_id("CVE-2026-84268");

  script_name(english:"Amazon Linux 2 : gvfs (ALAS-2026-3943)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The version of gvfs installed on the remote host is prior to 1.36.2-3. It is, therefore, affected by a vulnerability as
referenced in the ALAS2-2026-3943 advisory.

    A flaw was found in the SFTP backend in gvfs. When mounting a share and reading a file, a malicious SFTP
    server can cause read_reply() to process a length that exceeds the size requested by the client. The
    function does not verify the server-provided length against the allocated buffer size, causing the
    operation to write past the intended boundaries. This issue allows a malicious server to corrupt adjacent
    heap memory in the gvfsd-sftp process, resulting in a denial of service as the process aborts upon
    detecting the heap corruption or potentially allowing arbitrary code execution. (CVE-2026-84268)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue 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//AL2/ALAS2-2026-3943.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-2026-84268.html");
  script_set_attribute(attribute:"solution", value:
"Run 'yum update gvfs' or
  or 'yum update --advisory ALAS2-2026-3943' to update your system.");
  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:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-84268");

  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:"2026/09/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/28");
  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:gvfs");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-afc");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-afp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-archive");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-client");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-debuginfo");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-fuse");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-goa");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-gphoto2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-mtp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-smb");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:gvfs-tests");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
  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 != "2")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'gvfs-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afc-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afc-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afc-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afp-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afp-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-afp-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-archive-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-client-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debuginfo-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debuginfo-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-debuginfo-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-devel-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-devel-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-devel-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-fuse-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-goa-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-gphoto2-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-gphoto2-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-gphoto2-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-mtp-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-mtp-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-mtp-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-smb-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-tests-1.36.2-3.amzn2.0.3', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-tests-1.36.2-3.amzn2.0.3', 'cpu':'i686', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'gvfs-tests-1.36.2-3.amzn2.0.3', 'cpu':'x86_64', 'release':'AL2', '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, "gvfs / gvfs-afc / gvfs-afp / etc");
}