{"id":"CVE-2026-53939","summary":"OpenIDC/cjose uses all-zero Content Encryption Key for AES-CBC-HMAC JWE encryption","details":"OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). In versions 0.6.1 through 0.6.2.5, when cjose encrypts a JWE using an AES-CBC-HMAC content-encryption algorithm (`A128CBC-HS256`, `A192CBC-HS384`, or `A256CBC-HS512`) together with any key-management algorithm that generates a fresh content-encryption key (CEK), the CEK is all zero bytes instead of being randomly generated. The resulting JWE is therefore encrypted and authenticated under a fixed, publicly known key, so anyone who obtains the JWE can recover the plaintext and forge or modify the content. This is fixed in version 0.6.2.6 by `_cjose_jwe_set_cek_aes_cbc()` generating the CEK from `RAND_bytes`. A regression test asserts that the `encrypted_key` differs across two encryptions for each AES-CBC-HMAC variant. Until upgrading, for data encrypted with cjose, three options are available. Use an AES-GCM `enc` (`A128GCM` / `A192GCM` / `A256GCM`) instead of an AES-CBC-HMAC `enc`,  use `alg=dir` with a caller-supplied CEK, or avoid using cjose for JWE encryption with the affected algorithm pair. These are mitigations for new ciphertexts only; data already encrypted under the zero key remains compromised and should be re-encrypted (and any secrets it contained rotated).","aliases":["GHSA-f6wf-pqg3-6wqq"],"modified":"2026-10-29T22:57:03.603075480Z","published":"2026-09-08T23:36:13.668Z","related":["ALSA-2026:80605","ALSA-2026:92145","ALSA-2026:92157","SUSE-SU-2026:23910-1","SUSE-SU-2026:4237-1","SUSE-SU-2026:4251-1","SUSE-SU-2026:4253-1","openSUSE-SU-2026:11784-1","openSUSE-SU-2026:21944-1"],"database_specific":{"cwe_ids":["CWE-321","CWE-330"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53939.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/OpenIDC/cjose/releases/tag/v0.6.2.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53939.json"},{"type":"ADVISORY","url":"https://github.com/OpenIDC/cjose/security/advisories/GHSA-f6wf-pqg3-6wqq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53939"},{"type":"FIX","url":"https://github.com/OpenIDC/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/openidc/cjose","events":[{"introduced":"b122181f5537e928f8e78afd33f96a35bdefa67f"},{"fixed":"7d1aceae7da31fc6975db23f70f3c0485c5d5c43"},{"fixed":"2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9"}],"database_specific":{"extracted_events":[{"strategy":"StringRangeExpression","range":[{"introduced":"0.6.1"},{"fixed":"0.6.2.6"}],"source":"AFFECTED_FIELD"},{"range":[{"fixed":"2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9"}],"source":"REFERENCES_COMMIT"},{"source":"REFERENCES_TAG","original_tag":"v0.6.2.6","range":[{"fixed":"7d1aceae7da31fc6975db23f70f3c0485c5d5c43"}]}]}}],"versions":["v0.6.2.5","v0.6.2.4","v0.6.2.3","v0.6.2.2","v0.6.2.1","v0.6.2","latest","0.6.1"],"database_specific":{"vanir_signatures_modified":"2026-10-28T10:51:59Z","source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53939.json","vanir_signatures":[{"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["116477046408924815028086400580258302402","35270573579896220926845581587538046944","269347021087967161202338501076804441511","264825813263723684699009957575875684344","283644656238956572677772821184949171710","31346249582929627151043431563532097981","197839418495590472966498508209407985421"]},"id":"CVE-2026-53939-617de16e","signature_type":"Line","signature_version":"v1","source":"https://github.com/openidc/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9","target":{"file":"test/check_jwe.c"}},{"digest":{"function_hash":"235114565519311844344494074596621281681","length":1255},"id":"CVE-2026-53939-626334da","signature_type":"Function","signature_version":"v1","source":"https://github.com/openidc/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9","target":{"file":"test/check_jwe.c","function":"cjose_jwe_suite"},"deprecated":false},{"digest":{"function_hash":"81398865795572921431090125048300519039","length":1128},"id":"CVE-2026-53939-c2071872","signature_type":"Function","signature_version":"v1","source":"https://github.com/openidc/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9","target":{"file":"src/jwe.c","function":"_cjose_jwe_set_cek_aes_cbc"},"deprecated":false},{"source":"https://github.com/openidc/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9","target":{"file":"src/jwe.c"},"deprecated":false,"digest":{"line_hashes":["43495399126215342125969949187179913312","174249264605283481135370272835699076690","262396667104585820704651554589271265338","130510499250362651500522560773934573303","172875467020067064381028286810781091822","166376062333546220761724668685629877461","297757171072977877463593979263827555000"],"threshold":0.9},"id":"CVE-2026-53939-d23cba5a","signature_type":"Line","signature_version":"v1"}]}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}