{"id":"CVE-2026-63072","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-63072","summary":"Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based\non querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive\ncan write and cleanse more bytes…","details":"Issue summary: OpenSSL CMS decryption sizes the key-unwrap output buffer based\non querying the unwrapped key size, but the AES-WRAP-PAD unwrap primitive\ncan write and cleanse more bytes than that query reports, causing an 8-byte\nout-of-bounds heap write.\n\nImpact summary: An attacker who supplies a crafted CMS message can trigger a\ndeterministic 8-byte out-of-bounds heap write when the victim decrypts it\nwith CMS_decrypt(), corrupting the heap and typically resulting in a Denial\nof Service.\n\nCWE: CWE-787: Out-of-bounds Write\n\nDescription: The key-wrap OID is potentially attacker-controlled on the wire.\nCMS unwrapping allows both id-aesNNN-wrap-pad and id-aesNNN-wrap ciphers.\nAn attacker can take a legitimate message and change a single OID byte to\nselect the padded variant while leaving the message otherwise valid. Since\nthe unwrap key is derived from the recipient's private operation (ECDH key\nagreement or ML-KEM decapsulation), the RFC 5649 integrity check cannot\npass, and the decryption fails with integrity failure.\n\nThe write is a fixed-size (8-byte), fixed-value (zero) heap overflow\nimmediately past the allocation, requires no special configuration, and is\nreachable from the public CMS_decrypt() function. The consequence is\na heap corruption leading to a Denial of Service. The fix in the CMS code\nsizes the unwrap output buffer for the worst case so a failed unwrap cannot\nwrite past the allocation.\n\nFIPS impact: no\n\nAs the CMS code lives outside the FIPS module boundary, no FIPS\nmodules are affected by this CVE.","published":"2026-08-25T13:19:26.010","modified":"2026-08-25T13:19:26.010","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/openssl/openssl/commit/2a3dac874c8057c1f0186849bf1ede1ae7b6b756","label":"openssl/openssl@2a3dac8"},"references":[{"type":"WEB","url":"https://github.com/openssl/openssl/commit/2a3dac874c8057c1f0186849bf1ede1ae7b6b756"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/87784ad619af36b8807c2044b3940006fccc1e42"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/9530a5fd1aacaeccdced4478ea2340a480613335"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/9ec2f6d2ae2bcad907cf7ee38584855bafe4979a"},{"type":"WEB","url":"https://github.com/openssl/openssl/commit/a0c8ec557d9cac078f032d76cdf684fe743eb382"},{"type":"WEB","url":"https://openssl-library.org/news/secadv/20260825.txt"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-25T13:19:26.010"}}