Invalid Pointer Dereference in CMP Server via Crafted protectionAlg

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63076
StatePUBLISHED
Assigneropenssl
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-25 13:19:26 UTC
Updated2026-09-11 21:17:12 UTC
DescriptionIssue 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.013300000 probability, percentile 0.690430000 (date 2026-08-30)

Problem Types: CWE-476 | CWE-476 CWE-476 NULL Pointer Dereference

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Openssl Openssl All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenSSL OpenSSL affected 4.0.0 4.0.2 semver Not specified
CNA OpenSSL OpenSSL affected 3.6.0 3.6.4 semver Not specified
CNA OpenSSL OpenSSL affected 3.5.0 3.5.8 semver Not specified
CNA OpenSSL OpenSSL affected 3.4.0 3.4.7 semver Not specified
CNA OpenSSL OpenSSL affected 3.0.0 3.0.22 semver Not specified

References

ReferenceSourceLinkTags
openssl-library.org/news/secadv/20260825.txt [email protected] openssl-library.org Vendor Advisory
github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b [email protected] github.com Patch
github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c [email protected] github.com Patch
github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226 [email protected] github.com Patch
github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e [email protected] github.com Patch
github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259 [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Ying Dong (en)

CNA: Bhabani Sankar Das (en)

CNA: Daniel Kubec (en)

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