Linux Distros Unpatched Vulnerability : CVE-2026-85515

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

include('compat.inc');

if (description)
{
  script_id(362875);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/03");

  script_cve_id("CVE-2026-85515");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-85515");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - In Bouncy Castle for Java before 1.86, a truncated OpenPGP encrypted message was accepted with no error
    reported, and on the SEIPD version 1 path with no integrity check performed at all. RFC 9580 sec. 13.7
    permits an implementation to release the cleartext of the fully authenticated chunks when streaming but
    requires it to indicate a clear error as soon as the truncation is detected, and to report suspect
    integrity when it discovers malleable ciphertext. The truncation was detected and then discarded: when a
    message is truncated but the length field of the enclosing packet is left unchanged,
    BCPGInputStream.PartialInputStream raises an EOFException for the missing ciphertext, and
    BCPGInputStream.nextPacketTag() reports an EOFException as a clean end of message, so the packet stream
    above it stopped as though no packets remained. On the AEAD path (SEIPD version 2 and the version 5 AEAD
    packet), when the literal data packet ended on an AEAD chunk boundary and the consumer read in increments
    smaller than one chunk, the look-ahead for the packet after the literal triggered the truncated chunk
    read, so BcAEADUtil and JceAEADUtil never reached the trailing message tag of sec. 5.13.2 that
    authenticates the total plaintext length; the caller received the plaintext of the fully authenticated
    chunks, every packet following the literal was silently dropped, and no exception was raised, so a signed
    and encrypted message read back as a well-formed unsigned one. Every byte released on that path remained
    individually authenticated, making this a missing truncation error rather than a forgery, and it is a
    residual of CVE-2026-12817, which closed the same outcome for an attacker who corrects the outer packet
    length. On the SEIPD version 1 path the consequence was more serious: IntegrityProtectedInputStream
    verifies the modification detection code from close(), and reached close() only by closing itself when a
    read of it returned -1, which a truncated message never produces, so PGPEncryptedData.verify() never ran
    and the recipient was handed CFB-decrypted plaintext on which no integrity check of any kind had been
    performed. Measured on a message truncated into that shape, 136 distinct single-byte modifications of the
    ciphertext produced accepted, altered plaintext with no exception raised. Reachability is a property of
    the message rather than of attacker-supplied input: the AEAD shape held for 3 of 131 consecutive payload
    lengths measured, and the SEIPD version 1 shape for one payload length in sixteen, at a truncation offset
    that did not move with the payload length. The low-level API is unaffected, a caller that invokes
    PGPEncryptedData.verify() directly getting the check regardless, as are consumers reading in increments of
    a whole AEAD chunk or more. The AEAD decryption streams now re-throw such an EOFException as a plain
    IOException, which nextPacketTag() does not launder; OpenPGPMessageInputStream.close() now closes its
    layer's integrity-protected stream itself rather than relying on that stream having seen the end of its
    data; and IntegrityProtectedInputStream.close() was made idempotent, as java.io.Closeable requires, which
    that depends on, since the stream is genuinely closed twice on the ordinary path and
    PGPEncryptedData.verify() consumes the digest state behind it and cannot be run a second time. This issue
    also affects Bouncy Castle for Java LTS before 2.73.13, on the AEAD route only, as that edition does not
    ship the high-level OpenPGP API the SEIPDv1 route runs through. It also affects Bouncy Castle for Java
    FIPS (BC-FJA) before bcpg-fips 1.0.14 (1.0.X series), 2.0.14.1 (2.0.X series) and 2.1.14 (2.1.X series),
    on the AEAD route only, as those editions do not ship the high-level OpenPGP API. (CVE-2026-85515)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-85515");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/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:U/RC:C");
  script_set_attribute(attribute:"cvss4_vector", value:"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N");
  script_set_attribute(attribute:"cvss4_supplemental", value:"CVSS:4.0/U:Amber");
  script_set_attribute(attribute:"cvss4_threat_vector", value:"CVSS:4.0/E:U");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-85515");

  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_unpatched", value:"true");

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

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:bouncycastle");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  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", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "libbcjmail-java"},
          {"reference": "libbcmail-java"},
          {"reference": "libbcpg-java"},
          {"reference": "libbcpkix-java"},
          {"reference": "libbcprov-java"},
          {"reference": "libbctls-java"},
          {"reference": "libbcutil-java"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "libbcjmail-java"},
          {"reference": "libbcmail-java"},
          {"reference": "libbcpg-java"},
          {"reference": "libbcpkix-java"},
          {"reference": "libbcprov-java"},
          {"reference": "libbctls-java"},
          {"reference": "libbcutil-java"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');

var third_party_support = get_kb_item('Host/OS/extended-third-party');
if (!empty_or_null(third_party_support)) {
    var third_party_vendors = distro_constraints_values['third_party'];
    if (!empty_or_null(third_party_vendors)) {
        var vendor;
        foreach vendor (third_party_vendors) {
            if (vendor == third_party_support) exit(0, 'A third party management patch is available for this vulnerability from ' + vendor + '.\n');
        }
    }
}

var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}