AlmaLinux 9 : mod_http2 (ALSA-2026:25057)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The package checks in this plugin were extracted from
# AlmaLinux Security Advisory ALSA-2026:25057.
##

include('compat.inc');

if (description)
{
  script_id(320642);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/11");

  script_cve_id("CVE-2026-49975");
  script_xref(name:"ALSA", value:"2026:25057");
  script_xref(name:"RHSA", value:"2026:25057");

  script_name(english:"AlmaLinux 9 : mod_http2 (ALSA-2026:25057)");

  script_set_attribute(attribute:"synopsis", value:
"The remote AlmaLinux host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"The remote AlmaLinux 9 host has a package installed that is affected by a vulnerability as referenced in the
ALSA-2026:25057 advisory.

    * httpd: HTTP/2: Remote Denial of Service via compression bomb and Slowloris-style attack (CVE-2026-49975)

Tenable has extracted the preceding description block directly from the AlmaLinux 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://errata.almalinux.org/9/ALSA-2026-25057.html");
  script_set_attribute(attribute:"see_also", value:"https://access.redhat.com/errata/RHSA-2026:25057");
  script_set_attribute(attribute:"solution", value:
"Update the affected mod_http2 package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:N/I:N/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:N/VI:N/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-2026-49975");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_cwe_id(409);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/03");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/11");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:alma:linux:mod_http2");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::appstream");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::baseos");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::crb");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::highavailability");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::nfv");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::realtime");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::resilientstorage");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::sap");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::sap_hana");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:alma:linux:9::supplementary");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Alma 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/AlmaLinux/release", "Host/AlmaLinux/rpm-list", "Host/cpu");

  exit(0);
}


include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'AlmaLinux' >!< os_product) audit(AUDIT_OS_NOT, 'AlmaLinux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'AlmaLinux');
if (! preg(pattern:"^9([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'AlmaLinux 9.x', 'AlmaLinux ' + os_version);

if (!get_kb_item('Host/AlmaLinux/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

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

var constraints = [
  {
    'release': '9',
    'pkgs': [
      {'reference':'mod_http2-2.0.26-6.el9_8.1', 'cpu':'aarch64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'mod_http2-2.0.26-6.el9_8.1', 'cpu':'ppc64le', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'mod_http2-2.0.26-6.el9_8.1', 'cpu':'s390x', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'},
      {'reference':'mod_http2-2.0.26-6.el9_8.1', 'cpu':'x86_64', 'el_string':'el9_8', 'rpm_spec_vers_cmp':TRUE, 'epoch':'0'}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(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, 'mod_http2');
}