{"apiVersion":"1.0","identifier":"CVE-2026-63076","description":"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.","publishedAt":"2026-08-25T13:19:26","lastModifiedAt":"2026-08-25T15:16:36","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63076","cvssScore":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","epssProbability":0.0133,"riskScore":0.84,"affectedProduct":"OpenSSL","affectedVersions":"unknown","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-63076","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-63076","en":"https://www.redsauce.net/en/cves/CVE-2026-63076","fr":"https://www.redsauce.net/fr/cves/CVE-2026-63076","pt":"https://www.redsauce.net/pt/cves/CVE-2026-63076","de":"https://www.redsauce.net/de/cves/CVE-2026-63076","sk":"https://www.redsauce.net/sk/cves/CVE-2026-63076","el":"https://www.redsauce.net/el/cves/CVE-2026-63076"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-63076"}}