OpenSSL 1.1.1 < 1.1.1ze Multiple Vulnerabilities

This plugin (296769) bundles seven CVEs affecting OpenSSL 1.1.1 versions before 1.1.1ze, all disclosed between December 2025 and January 2026. The flaws are type-confusion bugs in PKCS#12 parsing (CVE-2025-69421, CVE-2025-69419, CVE-2026-22795), PKCS#7 signature verification (CVE-2026-22796), Timestamp Response verification (CVE-2025-69420), low-level OCB API handling (CVE-2025-69418), and BIO_f_linebuffer short writes (CVE-2025-68160). Every single one produces the same outcome: a crash (NULL pointer deref or invalid read) when the application processes attacker-crafted malformed input. No data exfiltration, no code execution, no privilege escalation — just denial of service.

Tenable's HIGH / CVSS 7.5 rating is an aggregation artifact — it inflates severity by combining multiple individually Low and Medium CVEs into one plugin. The OpenSSL project itself rated every one of these issues as Low severity, with the two January 2026 additions (CVE-2026-22795 and CVE-2026-22796) scoring CVSS 5.5 and 5.3 respectively. The vendor's own assessment is far more accurate here. Tenable's VPR of 7.0 (98th percentile) is also misleading given the absence of any exploitation evidence. Additionally, OpenSSL 1.1.1 has been EOL since September 2023 — patches are only available to premium support customers, which means most organizations running 1.1.1 are carrying broader crypto debt that matters more than these specific bugs.

Why this verdict

• All individual CVEs are Low/Medium: OpenSSL's own project rated every CVE in this bundle as Low severity. The two highest-scoring (CVE-2026-22795 at 5.5 and CVE-2026-22796 at 5.3) are Medium. Tenable's aggregate 7.5 is an artifact of bundling, not a reflection of any single exploitable flaw.
• Attack surface is narrow: Exploitation requires the victim application to parse untrusted PKCS#12, PKCS#7, or RFC 3161 data. The vast majority of OpenSSL deployments use it for TLS termination, where these code paths are never reached by external input. S/MIME verification gateways and certificate import workflows are the realistic vectors, representing a small fraction of the installed base.
• No exploitation evidence or PoC: Zero CVEs are KEV-listed, EPSS scores are below 1%, and no public proof-of-concept exists. The researcher (Aisle Research) performed coordinated disclosure without releasing exploit code.
• Role multiplier: OpenSSL is deployed across all role tiers — workstations, application servers, identity providers, edge appliances, and backup infrastructure. However, these specific CVEs only trigger via PKCS#12/PKCS#7/timestamp *parsing* of untrusted input, which is not a code path exercised in standard TLS serving. On a high-value target like an identity provider or edge appliance, the worst-case outcome is a service crash (availability impact) followed by automatic restart — not domain takeover, credential theft, or lateral movement. The DoS-only blast radius does not meet the HIGH floor threshold because no chain ends in fleet compromise or identity-scale impact.
• EOL amplifier noted but not severity-changing: OpenSSL 1.1.1 EOL status is a strategic risk (no free patches), but it does not increase the *technical* severity of these specific bugs. It belongs in remediation guidance, not the severity rating.

Why not higher?

These are DoS-only vulnerabilities with no demonstrated path to code execution. The one-byte out-of-bounds write in CVE-2025-69419 is constrained to a single byte before the buffer and is not believed exploitable for RCE. Without code execution, privilege escalation, or data access, the blast radius on even high-value targets is limited to temporary availability loss — recoverable via process restart. No KEV listing, no exploitation in the wild, and no public PoC further eliminate upward pressure.

Why not lower?

CVE-2026-22796 is network-reachable (AV:N) without authentication in applications that verify PKCS#7 signatures on untrusted input, such as S/MIME gateways. While the population of such applications is small, the unauthenticated remote DoS vector prevents a LOW rating. The sheer number of affected code paths (seven distinct bugs across three subsystems) also increases the probability that at least one vector is reachable in a given environment.

1. Migrate off OpenSSL 1.1.1 to a supported 3.x branch — This is the real fix. OpenSSL 1.1.1 has been EOL since September 2023 and carries accumulating unpatched risk beyond these seven CVEs. Plan migration to OpenSSL 3.4+ within the noisgate remediation SLA of 365 days for MEDIUM findings. If you have premium support, apply 1.1.1ze as an interim step.
2. Audit applications for untrusted PKCS#12/PKCS#7 input acceptance — Identify which applications call PKCS12_parse(), PKCS7_verify(), PKCS7_digest_from_attributes(), or TS_RESP_verify_response() on data from untrusted sources. If none do, your effective exposure is zero. Prioritize S/MIME gateways, certificate enrollment portals, and document signing services.
3. Use CMS APIs instead of legacy PKCS#7 APIs — OpenSSL recommends the CMS API over the PKCS#7 API. Applications using CMS equivalents are not affected by CVE-2026-22796. This is a code-level change for application developers.
4. Deploy WAF rules to inspect and reject malformed PKCS#7/PKCS#12 content types — If you have applications accepting signed data over HTTP, configure your WAF or reverse proxy to validate or reject application/pkcs7-mime and application/x-pkcs12 payloads that fail basic structural checks.

Run this on each target host as any user with read access to the OpenSSL binary. Example: bash check_openssl_1.1.1ze.sh or bash check_openssl_1.1.1ze.sh /usr/local/ssl/bin/openssl if OpenSSL is installed in a non-default location. No root privileges required.

#!/usr/bin/env bash
# check_openssl_1.1.1ze.sh — Verify whether host is vulnerable to Tenable 296769
# Checks for OpenSSL 1.1.1 < 1.1.1ze
# Exit codes: 0 = PATCHED, 1 = VULNERABLE, 2 = UNKNOWN

set -euo pipefail

OPENSSL_BIN="${1:-openssl}"

if ! command -v "$OPENSSL_BIN" &>/dev/null; then
  echo "UNKNOWN — openssl binary not found at '$OPENSSL_BIN'"
  exit 2
fi

VERSION_STRING=$("$OPENSSL_BIN" version 2>/dev/null)
if [[ -z "$VERSION_STRING" ]]; then
  echo "UNKNOWN — could not determine OpenSSL version"
  exit 2
fi

echo "Detected: $VERSION_STRING"

# Check if this is a 1.1.1 release
if [[ "$VERSION_STRING" =~ OpenSSL\ 1\.1\.1([a-z]*) ]]; then
  PATCH="${BASH_REMATCH[1]}"
  # 1.1.1ze is the minimum safe version
  # Patch letters: empty < a < b < ... < z < za < zb < ... < ze
  if [[ -z "$PATCH" ]]; then
    echo "VULNERABLE — OpenSSL 1.1.1 (no patch letter) is affected"
    exit 1
  elif [[ ${#PATCH} -eq 1 ]]; then
    # Single letter: a-z, all vulnerable (need ze which is 2 chars)
    echo "VULNERABLE — OpenSSL 1.1.1${PATCH} is below 1.1.1ze"
    exit 1
  elif [[ ${#PATCH} -eq 2 && "${PATCH:0:1}" == "z" ]]; then
    SECOND="${PATCH:1:1}"
    # Compare second character: a,b,c,d are below e
    if [[ "$SECOND" < "e" ]]; then
      echo "VULNERABLE — OpenSSL 1.1.1${PATCH} is below 1.1.1ze"
      exit 1
    else
      echo "PATCHED — OpenSSL 1.1.1${PATCH} is at or above 1.1.1ze"
      exit 0
    fi
  else
    # 3+ char patch or non-z prefix — likely newer
    echo "PATCHED — OpenSSL 1.1.1${PATCH} appears to be at or above 1.1.1ze"
    exit 0
  fi
elif [[ "$VERSION_STRING" =~ OpenSSL\ ([0-9]+)\.([0-9]+)\.([0-9]+) ]]; then
  MAJOR="${BASH_REMATCH[1]}"
  MINOR="${BASH_REMATCH[2]}"
  # OpenSSL 3.x — not affected by this specific plugin (different branch)
  # OpenSSL 1.0.x — different plugin covers that
  if [[ "$MAJOR" -ge 3 ]]; then
    echo "PATCHED — OpenSSL ${MAJOR}.${MINOR}.x is not in the 1.1.1 branch (check separate plugins for 3.x vulns)"
    exit 0
  else
    echo "UNKNOWN — OpenSSL ${MAJOR}.${MINOR}.x detected; this script checks 1.1.1 only"
    exit 2
  fi
else
  echo "UNKNOWN — version string '$VERSION_STRING' does not match expected OpenSSL format"
  exit 2
fi

Sources

1. Tenable Plugin 296769
2. OpenSSL 1.1.1 Vulnerabilities List
3. OpenSSL Security Advisory (Jan 2026, corrected)
4. CVE-2026-22796 — NVD Detail
5. Node.js OpenSSL Assessment (Jan 2026)
6. Red Hat RHSA-2026:1473
7. OpenSSL 1.1.1 EOL Announcement
8. Aisle Research — 12 OpenSSL Vulnerabilities