{"id":"CVE-2026-63076","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-63076","summary":"Issue summary: OpenSSL CMP password based protection verification only\nchecks whether the protectionAlg parameter was not NULL and not its\nASN.1 type, before treating it as a PBMParameter.…","details":"Issue summary: OpenSSL CMP password based protection verification only\nchecks whether the protectionAlg parameter was not NULL and not its\nASN.1 type, before treating it as a PBMParameter. A crafted message can\ncontain a parameter of a different type, which is then dereferenced as an\ninvalid pointer.\n\nImpact summary: A remote, unauthenticated attacker can crash an application\nacting as a CMP server that accepts PBM-protected messages, or a CMP client\ntalking to a malicious or intercepted CMP server, resulting in a Denial of\nService.\n\nCWE: CWE-476: NULL Pointer Dereference\n\nDescription: When verifying the password-based MAC protection of a CMP\nmessage, OpenSSL library reads the protectionAlg algorithm parameter with\nX509_ALGOR_get0(), which returns both the parameter type and its value\npointer. The value is then cast to an ASN1_STRING and treated as the\nexpected PBMParameter after only checking that pointer is not NULL. The\nparameter type returned by X509_ALGOR_get0() was never consulted.\n\nThis happens during protection verification, before any MAC is computed, so\nno knowledge of the PBM shared secret is required; the only precondition is\nthat PBM verification is reachable. On the server side this is reached from\nOSSL_CMP_SRV_process_request() for any application that stands up a CMP\nserver accepting PBM-protected messages, and on the client side from CMP\nresponse validation against a malicious or on-path (MITM) server. The\nreliable consequence is a denial of service; there is no memory disclosure,\nno controlled memory write, and no path to code execution. CMP is a\nspecialized feature that an application must explicitly enable.\n\nFIPS impact: no\nAs the CMP code lives outside the FIPS module boundary, no FIPS modules\nare affected by this CVE.","published":"2026-08-25T13:19:26.543","modified":"2026-08-25T13:19:26.543","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b","label":"openssl/openssl@37882aa"},"references":[{"type":"WEB","url":"https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c"},{"type":"WEB","url":"https://openssl-library.org/news/secadv/20260825.txt"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-25T13:19:26.543"}}