CentOS Linux 8 [TuxCare] Security Update: openssl / openssl-devel / openssl-libs / openssl-perl / etc Multiple Vulnerabilities (CENTOS-STREAM8:CLSA-2026:1785335298)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(352442);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/30");

  script_cve_id(
    "CVE-2026-7383",
    "CVE-2026-9076",
    "CVE-2026-34180",
    "CVE-2026-42766",
    "CVE-2026-42768"
  );
  script_xref(name:"CLSA", value:"2026:1785335298");

  script_name(english:"CentOS Linux 8 [TuxCare] Security Update: openssl / openssl-devel / openssl-libs / openssl-perl / etc Multiple Vulnerabilities (CENTOS-STREAM8:CLSA-2026:1785335298)");

  script_set_attribute(attribute:"synopsis", value:
"The CentOS Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The CentOS Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the
TuxCare CENTOS-STREAM8:CLSA-2026:1785335298 advisory.

  - Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content
    exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms.
    Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into
    the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1
    elements would instead be truncated. An integer truncation in OpenSSL's ASN.1 decoder causes the content
    length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the
    truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly
    causing OpenSSL to read either less than or beyond the end of the allocated buffer. Applications that pass
    attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected.
    OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before
    it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms
    and 64-bit Windows are not affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by
    this issue, as the affected code is outside the OpenSSL FIPS module boundary. (CVE-2026-34180)

  - Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference
    during CMS decryption. Impact summary: This NULL pointer dereference leads to an application crash and a
    Denial of Service. The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in
    the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based
    CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it
    was present. An attacker who supplies such a CMS message to an application performing password-based CMS
    decryption can trigger an application crash, leading to a Denial of Service. Applications that process
    password-encrypted CMS messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not
    affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary. (CVE-2026-42766)

  - Issue summary: The CMS_decrypt and PKCS7_decrypt functions are vulnerable to Bleichenbacher-style attack
    when an attacker is able to provide the CMS or S/MIME messages and observe the error code and/or
    decryption output. Impact summary: The Bleichenbacher-style attack allows an attacker to use the victim's
    vulnerable application as a way to decrypt or sign messages with the victim's private RSA key. The attack
    is possible in 2 variants. 1. The decryption API (CMS_decrypt(), PKCS7_decrypt()) is used without
    providing the recipient certificate. In this case OpenSSL iterates over every KeyTransRecipientInfo (KTRI)
    without stopping at the first success. An attacker who authors a message with two KTRI entries  the first
    one wrapping a real CEK under the victim's public key, the second with an arbitrary probe ciphertext 
    obtains opportunity to iterate the 2nd KTRI to get a valid PKCS#1 v1.5 padding if the error code of the
    application is available. That is a Bleichenbacher oracle (Bleichenbacher, CRYPTO '98): an adaptive-
    chosen-ciphertext side channel from which the attacker decrypts any RSA ciphertext to the victim's key or
    forges any PKCS#1 v1.5 signature under it. 2. When the decryption API (CMS_decrypt(), PKCS7_decrypt()) is
    provided with the recipient certificate, and the recipient is not found, a random key is substituted. An
    attacker who authors a message and is able to compare both error code and the result of the decryption,
    can mount a Bleichenbacher oracle. We are not aware of any applications that provide a remote attacker an
    opportunity to mount an attack described in these scenarios. We consider the existence of such application
    very unlikely, and for this reason this CVE has been evaluated as Low severity. To avoid these attacks,
    when RSA PKCS#1 v1.5 Key Transport is in use, the invoked EVP_PKEY_decrypt() will use the implicit
    rejection mechanism described in draft-irtf-cfrg-rsa-guidance. In previous OpenSSL releases the implicit
    rejection was explicitly disabled. The implicit rejection mechanism always returns a plaintext value, the
    symmetric key. This result is deterministic for the ciphertext and the private key. The length of the
    decryption result can happen to match the length of the key of the symmetric cipher that was used for the
    content encryption. When a certificate is not provided, the last RecipientInfo producing a key that looks
    valid will be used. It may cause getting garbage content on decryption. As a proper way to deal with this
    a recipient certificate has to be provided to identify the particular RecipientInfo for decryption. The
    FIPS modules in 4.0, 3.6, 3.5, and 3.4 are not affected by this issue, as CMS and S/MIME processing
    happens outside the OpenSSL FIPS module boundary. (CVE-2026-42768)

  - Issue summary: A signed integer overflow when sizing the destination buffer for Unicode output in
    ASN1_mbstring_ncopy() can lead to a heap buffer overflow. Impact summary: A heap buffer overflow may lead
    to a crash or possibly attacker controlled code execution or other undefined behaviour. In
    ASN1_mbstring_copy() and ASN1_mbstring_ncopy() the destination size for Unicode output is computed in a
    signed int: by left shift of the input character count for BMPSTRING (UTF-16) and UNIVERSALSTRING
    (UTF-32), and by summing per-character byte counts for UTF8STRING. The calculation overflows when the
    input reaches around 2^30 characters. In the worst case (UNIVERSALSTRING at 2^30 characters) the size
    wraps to zero, OPENSSL_malloc(1) is called, and the subsequent character copy writes several gigabytes
    past the one-byte allocation. X.509 certificate processing routes through ASN1_STRING_set_by_NID(), whose
    DIRSTRING_TYPE mask excludes UNIVERSALSTRING and whose per-NID size limits cap the input length; no
    network protocol or certificate-handling path in OpenSSL exercises the overflow. Triggering the bug
    requires an application that calls ASN1_mbstring_copy() or ASN1_mbstring_ncopy() directly, or registers a
    custom string type via ASN1_STRING_TABLE_add(), with attacker-controlled input on the order of half a
    gigabyte or more. For these reasons this issue was assigned Low severity. The FIPS modules in 4.0, 3.6,
    3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module
    boundary. (CVE-2026-7383)

  - Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap) processes attacker-supplied
    CMS data, an attacker-chosen stream-mode KEK cipher can trigger a heap out-of-bounds read in
    kek_unwrap_key(). Impact summary: A heap buffer over-read may trigger a crash which leads to Denial of
    Service for an application if the input buffer ends at a memory page boundary and the following page is
    unmapped. There is no information disclosure as the over-read bytes are not revealed to the attacker. The
    key unwrapping function performs a check-byte test as specified in the RFC that reads 7 bytes from a heap
    allocation that is based on the wrapped key length from the message. There is a minimum length check based
    on the block length of the wrapping cipher. However the cipher is selected from an OID carried in the
    attacker's PWRI keyEncryptionAlgorithm with no requirement that the cipher be a block cipher. When an
    attacker selects a stream-mode cipher the guard will be ineffective and the allocated buffer containing
    the unwrapped key can be too small to fit the check-bytes specified in the RFC and a buffer over-read can
    happen. Applications calling CMS_decrypt() or CMS_decrypt_set1_password() (equivalently openssl cms
    -decrypt -pwri_password ...) on untrusted CMS data are vulnerable to this issue. No password knowledge is
    required: the over-read happens during the unwrap attempt before any authentication succeeds. The over-
    read is limited to a few bytes and is not written to output, so there is no information disclosure.
    Triggering a crash requires the allocation to border unmapped memory, which is unlikely with the normal
    allocator. The FIPS modules are not affected by this issue. (CVE-2026-9076)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://security.tuxcare.com/csaf/v2/els_os/centos-stream8els/advisories/2026/clsa-2026_1785335298.json
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?4e4de8b5");
  script_set_attribute(attribute:"see_also", value:"https://cve.tuxcare.com/els/releases/CLSA-2026:1785335298");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages based on the guidance in TuxCare advisory CENTOS-STREAM8:CLSA-2026:1785335298.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/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:H/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:"cvss_score_source", value:"CVE-2026-7383");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_set_attribute(attribute:"vendor_severity", value:"Important");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/06/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/07/29");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/30");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"CentOS 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/OS/extended-third-party", "Host/local_checks_enabled", "Host/CentOS/release", "Host/CentOS/rpm-list");

  exit(0);
}
include('rpm2.inc');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (empty_or_null(third_party_support) || third_party_support != 'TuxCare') exit(0, 'TuxCare support not enabled.');

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) || 'CentOS Linux' >!< os_product) audit(AUDIT_OS_NOT, 'CentOS Linux');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'CentOS Linux');
if (! preg(pattern:"^8([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'CentOS Linux 8', 'CentOS Linux ' + os_version);

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

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


var constraints = [
  {
    'release': '8',
    'pkgs': [
      {'reference':'openssl-1.1.1k-12.el8.tuxcare.els10', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-devel-1.1.1k-12.el8.tuxcare.els10', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-devel-1.1.1k-12.el8.tuxcare.els10', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-libs-1.1.1k-12.el8.tuxcare.els10', 'cpu':'i686', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-libs-1.1.1k-12.el8.tuxcare.els10', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-perl-1.1.1k-12.el8.tuxcare.els10', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'},
      {'reference':'openssl-static-1.1.1k-12.el8.tuxcare.els10', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE, 'epoch':'1'}
    ]
  }
];

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, 'openssl / openssl-devel / openssl-libs / openssl-perl / etc');
}