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Memory Corruption

CVE-2026-63076

CVE-2026-63076 — Invalid Pointer Dereference in CMP Server via Crafted protectionAlg

Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before treating it as a PBMParameter. A crafted message can contain a parameter of a different type, which is then dereferenced as an invalid pointer. Impact summary: A remote, unauthenticated attacker can crash an application acting as a CMP server that accepts PBM-protected messages, or a CMP client talking to a malicious or intercepted CMP server, resulting in a Denial of Service. CWE: CWE-476: NULL Pointer Dereference Description: When verifying the password-based MAC protection of a CMP message, OpenSSL library reads the protectionAlg algorithm parameter with X509_ALGOR_get0(), which returns both the parameter type and its value pointer. The value is then cast to an ASN1_STRING and treated as the expected PBMParameter after only checking that pointer is not NULL. The parameter type returned by X509_ALGOR_get0() was never consulted. This happens during protection verification, before any MAC is computed, so no knowledge of the PBM shared secret is required; the only precondition is that PBM verification is reachable. On the server side this is reached from OSSL_CMP_SRV_process_request() for any application that stands up a CMP server accepting PBM-protected messages, and on the client side from CMP response validation against a malicious or on-path (MITM) server. The reliable consequence is a denial of service; there is no memory disclosure, no controlled memory write, and no path to code execution. CMP is a specialized feature that an application must explicitly enable. FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.

Published Updated Sources: NVD, OpenSSL (CNA), GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

ahead of 0% of scored CVEs

Affects

OpenSSL

5 products listed

CVSS base

Unscored

no source published a base score

Remediation

The vendor's own words where we have them.

Upgrade OpenSSL to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Prioritize based on EPSS, PoC availability, and external exposure.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
OpenSSLOpenSSL4.0.0 to < 4.0.2Vulnerable
OpenSSLOpenSSL3.6.0 to < 3.6.4Vulnerable
OpenSSLOpenSSL3.5.0 to < 3.5.8Vulnerable
OpenSSLOpenSSL3.4.0 to < 3.4.7Vulnerable
OpenSSLOpenSSL3.0.0 to < 3.0.22Vulnerable

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-476 · NULL Pointer Dereference

  • DoS: Crash, Exit, or Restart
  • Execute Unauthorized Code or Commands
  • Read Memory
  • Modify Memory

Mitigation: If all pointers that could have been modified are sanity-checked previous to use, nearly all NULL pointer dereferences can be prevented.

Weakness & attack patterns

  • CWE-476NULL Pointer Dereference

Inferred from the weakness class — not observed against this CVE.

CAPEC-100 · Overflow BuffersCAPEC-123 · Buffer Manipulation

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026
  2. Initial · CVE published

    Aug 25, 2026 · NVD

References

6 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-63076 is Invalid Pointer Dereference in CMP Server via Crafted protectionAlg, a unscored vulnerability affecting OpenSSL from OpenSSL. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-63076. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-63076. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS null describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.