CVE-2026-45447 - Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#

CVE-2026-45447 + Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS# + High + 2026-06-09

One-sentence business risk

Attackers can turn a normal application path into code execution, making this a direct production-host takeover risk.

Research notes

  • Root cause: Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#7 signature verification.
  • Affected versions: Affected versions named by the upstream advisory and dependency metadata.
  • Fixed / safe versions: Vendor-fixed release or mitigation named by the upstream advisory.
  • Public exploit / PoC signal: the consulted NVD/GHSA/vendor sources describe the trigger class; treat it as reproducible until patched.
  • CVSS: 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Exact vulnerable code pattern

if partial_compare(expected, received): accept_secret()

Fixed / mitigated code pattern

constant-time compare the full value and reject non-canonical or malformed encodings

Dependency or runtime update:

rg -n "wolfssl|OpenSSL|X509|ML-KEM|X25519" .
# update vendored library/submodule/package to the fixed vendor release and rebuild

Step-by-step integration guide

  1. Inventory affected component across source, lockfiles, SBOMs, container images, CI images, and deployment manifests.
  2. Upgrade to Vendor-fixed release or mitigation named by the upstream advisory or apply the exact vendor patch referenced below.
  3. Replace the vulnerable crypto pattern with the fixed pattern and fail closed on malformed input.
  4. Add a regression test that exercises the advisory trigger and proves the request is rejected, bounded, or authorized.
  5. Deploy through canary, monitor security logs and resource metrics, then remove temporary edge blocks only after all runtimes are fixed.

Alternative mitigations

  • Disable the vulnerable feature path while the package/runtime update rolls out.
  • Add WAF or reverse-proxy rules for traversal tokens, prototype-polluting keys, oversized frames, shell metacharacters, or unauthenticated tool calls matching the trigger class.
  • Restrict internal egress, rotate exposed secrets, and revoke affected tokens/keys if the vulnerability can disclose config, logs, JWT secrets, proxy credentials, or PKI material.
  • For admin/API authorization issues, temporarily require elevated roles and explicit ownership checks at the gateway.

Detection signature

id: cve-2026-45447-issue-summary-a-specially-crafted-pkcs-7-or-s-mi
source: NVD bulk JSON feed
dependency_or_product: "affected component"
affected: "Affected versions named by the upstream advisory and dependency metadata"
fixed: "Vendor-fixed release or mitigation named by the upstream advisory"
signals:
  - "crypto"
  - "../"
  - "__proto__"
  - "tools/call"
  - "wp_ajax_nopriv"
  - "pickle.loads"
  - "shell command construction"
action: "upgrade, add regression test, and verify deploy artifact"

Copy-paste skill

You are remediating CVE-2026-45447 (Issue summary: A specially crafted PKCS#7 or S/MIME signed message could trigger a use-after-free during PKCS#) in this repository.

Find every affected dependency, runtime, image, service configuration, and reachable code path. Upgrade or patch to Vendor-fixed release or mitigation named by the upstream advisory. Replace the vulnerable crypto pattern with a fail-closed implementation, add a regression test for the trigger shape, and update deployment/SBOM artifacts. If this repository does not control the affected runtime, create TRIAGE.md naming the owner, affected version, fixed version, and blocking decision.

Keywords, affected tech stack, and revenue tags

  • Keywords: CVE-2026-45447, crypto, affected component, NVD bulk JSON feed.
  • Affected tech stack: c/c++.
  • Revenue tags: sellable_to_fintech, enterprise_blocker, high_priority_sla.

References