{"id":"CVE-2026-75805","state":"PUBLISHED","title":"NULL Pointer Dereference in CMP Client Revocation Response Handling","description":"Issue summary: A CMP client that requests certificate revocation on the basis\nof a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when\nprocessing a crafted revocation response. \n\nImpact summary: The NULL pointer dereference happens on a read which \nleads to a crash and a Denial of Service for the affected client application.\n\nCWE: CWE-476: NULL-pointer dereference\n\nDescription: A CMP client revoking a certificate has to tell the server which\ncertificate to revoke, and may do so by supplying a PKCS#10 CSR instead of the\ncertificate itself or its issuer name and serial number. This is\n'openssl cmp -cmd rr -csr <file>' on the command line, or\nOSSL_CMP_exec_RR_ses() with the certificate supplied via\nOSSL_CMP_CTX_set1_p10CSR() through the API.\n\nA CSR does not contain the issuer name and serial number of the certificate,\nso the client does not send them. A server may optionally name the\ncertificate it revoked in its response, and the client then compares that\nname against what it sent. Having sent neither an issuer name nor a serial\nnumber, it has nothing to compare against, and a server returning a specially\ncrafted name causes the client to read from a NULL pointer and crash.\n\nThe revocation response is checked for valid message protection before\nthe affected code is reached, so an attacker must be a malicious or\ncompromised CMP server, or a man-in-the-middle in possession of the\nsecret used for message protection. Clients that identify the certificate\nto be revoked by a certificate or by issuer and serial number rather\nthan by a PKCS#10 CSR are not affected.\n\nFIPS impact: no\nNo FIPS modules are affected by this issue, as the CMP protocol\nimplementation is outside the OpenSSL FIPS module boundary.","publishedAt":"2026-09-29T15:32:20.408Z","updatedAt":"2026-09-29T16:54:39.263Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","source":"CISA-ADP"},"assigner":"openssl","products":["OpenSSL OpenSSL"],"affected":[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThan":"4.0.3","versionType":"semver"},{"version":"3.6.0","status":"affected","lessThan":"3.6.5","versionType":"semver"},{"version":"3.5.0","status":"affected","lessThan":"3.5.9","versionType":"semver"},{"version":"3.4.0","status":"affected","lessThan":"3.4.8","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.23","versionType":"semver"}]}],"references":["https://openssl-library.org/news/secadv/20260929.txt","https://github.com/openssl/openssl/commit/7ca0ccb5172a577e9b87267d77bfe21e5481a5e7","https://github.com/openssl/openssl/commit/7588db7fef14209c3caa3a101d11a02006b19166","https://github.com/openssl/openssl/commit/9eb2a8a9b86136cdb39d6d7d50644dd66941cdc3","https://github.com/openssl/openssl/commit/abf02872a4b71767ecc72293424420f5b009190f"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/75xxx/CVE-2026-75805.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75805","state":"PUBLISHED","datePublished":"2026-09-29T15:32:20.408Z","dateUpdated":"2026-09-29T16:54:39.263Z","assignerShortName":"openssl","assignerOrgId":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","dateReserved":"2026-08-18T09:34:32.659Z"},"containers":{"cna":{"title":"NULL Pointer Dereference in CMP Client Revocation Response Handling","descriptions":[{"lang":"en","value":"Issue summary: A CMP client that requests certificate revocation on the basis\nof a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when\nprocessing a crafted revocation response. \n\nImpact summary: The NULL pointer dereference happens on a read which \nleads to a crash and a Denial of Service for the affected client application.\n\nCWE: CWE-476: NULL-pointer dereference\n\nDescription: A CMP client revoking a certificate has to tell the server which\ncertificate to revoke, and may do so by supplying a PKCS#10 CSR instead of the\ncertificate itself or its issuer name and serial number. This is\n'openssl cmp -cmd rr -csr <file>' on the command line, or\nOSSL_CMP_exec_RR_ses() with the certificate supplied via\nOSSL_CMP_CTX_set1_p10CSR() through the API.\n\nA CSR does not contain the issuer name and serial number of the certificate,\nso the client does not send them. A server may optionally name the\ncertificate it revoked in its response, and the client then compares that\nname against what it sent. Having sent neither an issuer name nor a serial\nnumber, it has nothing to compare against, and a server returning a specially\ncrafted name causes the client to read from a NULL pointer and crash.\n\nThe revocation response is checked for valid message protection before\nthe affected code is reached, so an attacker must be a malicious or\ncompromised CMP server, or a man-in-the-middle in possession of the\nsecret used for message protection. Clients that identify the certificate\nto be revoked by a certificate or by issuer and serial number rather\nthan by a PKCS#10 CSR are not affected.\n\nFIPS impact: no\nNo FIPS modules are affected by this issue, as the CMP protocol\nimplementation is outside the OpenSSL FIPS module boundary."}],"affected":[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThan":"4.0.3","versionType":"semver"},{"version":"3.6.0","status":"affected","lessThan":"3.6.5","versionType":"semver"},{"version":"3.5.0","status":"affected","lessThan":"3.5.9","versionType":"semver"},{"version":"3.4.0","status":"affected","lessThan":"3.4.8","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.23","versionType":"semver"}]}],"references":[{"url":"https://openssl-library.org/news/secadv/20260929.txt","name":"OpenSSL Advisory","tags":["vendor-advisory"]},{"url":"https://github.com/openssl/openssl/commit/7ca0ccb5172a577e9b87267d77bfe21e5481a5e7","name":"4.0.3 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/7588db7fef14209c3caa3a101d11a02006b19166","name":"3.6.5 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/9eb2a8a9b86136cdb39d6d7d50644dd66941cdc3","name":"3.5.9 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/abf02872a4b71767ecc72293424420f5b009190f","name":"3.4.8 git commit","tags":["patch"]}],"metrics":[{"format":"other","other":{"content":{"text":"Low"},"type":"https://openssl-library.org/policies/general/security-policy/"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","description":"CWE-476 NULL-pointer dereference","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"openssl","orgId":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","dateUpdated":"2026-09-29T15:32:20.408Z"},"credits":[{"lang":"en","type":"reporter","value":"Bhabani Sankar Das"},{"lang":"en","type":"remediation developer","value":"Bhabani Sankar Das"},{"lang":"en","type":"remediation developer","value":"Norbert Pocs"}],"datePublic":"2026-09-29T14:21:57.000Z","source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.3,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"LOW","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-09-29T16:54:03.315064Z","id":"CVE-2026-75805","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-29T16:54:39.263Z"}}]}}}