{"id":"CVE-2026-9076","state":"PUBLISHED","title":"Out-of-Bounds Read in CMS Password-Based Decryption","description":"Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap)\nprocesses attacker-supplied CMS data, an attacker-chosen stream-mode KEK\ncipher can trigger a heap out-of-bounds read in kek_unwrap_key().\n\nImpact summary: A heap buffer over-read may trigger a crash which leads to\nDenial of Service for an application if the input buffer ends at a memory\npage boundary and the following page is unmapped. There is no information\ndisclosure as the over-read bytes are not revealed to the attacker.\n\nThe key unwrapping function performs a check-byte test as specified in the\nRFC that reads 7 bytes from a heap allocation that is based on the wrapped\nkey length from the message. There is a minimum length check based on the\nblock length of the wrapping cipher. However the cipher is selected from\nan OID carried in the attacker's PWRI keyEncryptionAlgorithm with no\nrequirement that the cipher be a block cipher. When an attacker selects\na stream-mode cipher the guard will be ineffective and the allocated buffer\ncontaining the unwrapped key can be too small to fit the check-bytes\nspecified in the RFC and a buffer over-read can happen.\n\nApplications calling CMS_decrypt() or CMS_decrypt_set1_password()\n(equivalently openssl cms -decrypt -pwri_password ...) on untrusted CMS\ndata are vulnerable to this issue. No password knowledge is required: the\nover-read happens during the unwrap attempt before any authentication\nsucceeds.\n\nThe over-read is limited to a few bytes and is not written to output, so\nthere is no information disclosure. Triggering a crash requires the\nallocation to border unmapped memory, which is unlikely with the normal\nallocator.\n\nThe FIPS modules are not affected by this issue.","publishedAt":"2026-06-09T16:03:16.306Z","updatedAt":"2026-06-10T07:47:51.139Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"openssl","products":["OpenSSL OpenSSL"],"affected":[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThan":"4.0.1","versionType":"semver"},{"version":"3.6.0","status":"affected","lessThan":"3.6.3","versionType":"semver"},{"version":"3.5.0","status":"affected","lessThan":"3.5.7","versionType":"semver"},{"version":"3.4.0","status":"affected","lessThan":"3.4.6","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.21","versionType":"semver"},{"version":"1.1.1","status":"affected","lessThan":"1.1.1zh","versionType":"custom"},{"version":"1.0.2","status":"affected","lessThan":"1.0.2zq","versionType":"custom"}]}],"references":["https://openssl-library.org/news/secadv/20260609.txt","https://github.com/openssl/openssl/commit/3d8d5bc1056b2f62da9fede23fedbf47e85187b0","https://github.com/openssl/openssl/commit/77bf00ab13f6ff5e516535432f0328ed70ec0c26","https://github.com/openssl/openssl/commit/715349a1d7c6db970e6815dafb90915f07307f98","https://github.com/openssl/openssl/commit/05b066366842f930fadd9a6e94df98030af431bb","https://github.com/openssl/openssl/commit/eecbe330977e8d023aae1ca2d9bdbe983ef3fdc6"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:13:52.441Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/9xxx/CVE-2026-9076.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-9076","state":"PUBLISHED","datePublished":"2026-06-09T16:03:16.306Z","dateUpdated":"2026-06-10T07:47:51.139Z","assignerShortName":"openssl","assignerOrgId":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","dateReserved":"2026-05-20T12:43:37.677Z"},"containers":{"cna":{"title":"Out-of-Bounds Read in CMS Password-Based Decryption","descriptions":[{"lang":"en","value":"Issue summary: When CMS password-based decryption (RFC 3211 / PWRI key unwrap)\nprocesses attacker-supplied CMS data, an attacker-chosen stream-mode KEK\ncipher can trigger a heap out-of-bounds read in kek_unwrap_key().\n\nImpact summary: A heap buffer over-read may trigger a crash which leads to\nDenial of Service for an application if the input buffer ends at a memory\npage boundary and the following page is unmapped. There is no information\ndisclosure as the over-read bytes are not revealed to the attacker.\n\nThe key unwrapping function performs a check-byte test as specified in the\nRFC that reads 7 bytes from a heap allocation that is based on the wrapped\nkey length from the message. There is a minimum length check based on the\nblock length of the wrapping cipher. However the cipher is selected from\nan OID carried in the attacker's PWRI keyEncryptionAlgorithm with no\nrequirement that the cipher be a block cipher. When an attacker selects\na stream-mode cipher the guard will be ineffective and the allocated buffer\ncontaining the unwrapped key can be too small to fit the check-bytes\nspecified in the RFC and a buffer over-read can happen.\n\nApplications calling CMS_decrypt() or CMS_decrypt_set1_password()\n(equivalently openssl cms -decrypt -pwri_password ...) on untrusted CMS\ndata are vulnerable to this issue. No password knowledge is required: the\nover-read happens during the unwrap attempt before any authentication\nsucceeds.\n\nThe over-read is limited to a few bytes and is not written to output, so\nthere is no information disclosure. Triggering a crash requires the\nallocation to border unmapped memory, which is unlikely with the normal\nallocator.\n\nThe FIPS modules are not affected by this issue."}],"affected":[{"vendor":"OpenSSL","product":"OpenSSL","defaultStatus":"unaffected","versions":[{"version":"4.0.0","status":"affected","lessThan":"4.0.1","versionType":"semver"},{"version":"3.6.0","status":"affected","lessThan":"3.6.3","versionType":"semver"},{"version":"3.5.0","status":"affected","lessThan":"3.5.7","versionType":"semver"},{"version":"3.4.0","status":"affected","lessThan":"3.4.6","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.21","versionType":"semver"},{"version":"1.1.1","status":"affected","lessThan":"1.1.1zh","versionType":"custom"},{"version":"1.0.2","status":"affected","lessThan":"1.0.2zq","versionType":"custom"}]}],"references":[{"url":"https://openssl-library.org/news/secadv/20260609.txt","name":"OpenSSL Advisory","tags":["vendor-advisory"]},{"url":"https://github.com/openssl/openssl/commit/3d8d5bc1056b2f62da9fede23fedbf47e85187b0","name":"4.0.1 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/77bf00ab13f6ff5e516535432f0328ed70ec0c26","name":"3.6.3 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/715349a1d7c6db970e6815dafb90915f07307f98","name":"3.5.7 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/05b066366842f930fadd9a6e94df98030af431bb","name":"3.4.6 git commit","tags":["patch"]},{"url":"https://github.com/openssl/openssl/commit/eecbe330977e8d023aae1ca2d9bdbe983ef3fdc6","name":"3.0.21 git commit","tags":["patch"]}],"metrics":[{"format":"other","other":{"content":{"text":"Low"},"type":"https://openssl-library.org/policies/general/security-policy/"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","description":"CWE-125 Out-of-bounds Read","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"openssl","orgId":"3a12439a-ef3a-4c79-92e6-6081a721f1e5","dateUpdated":"2026-06-10T07:47:51.139Z"},"credits":[{"lang":"en","type":"reporter","value":"Bhabani Sankar Das"},{"lang":"en","type":"reporter","value":"Haruki Oyama (Waseda University)"},{"lang":"en","type":"remediation developer","value":"Nikola Pajkovsky"}],"datePublic":"2026-06-09T14:00:00.000Z","source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-06-09T19:04:07.840133Z","id":"CVE-2026-9076","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":"2026-06-09T19:04:20.258Z"}}]}}}