CMS AuthEnvelopedData Processing May Accept Forged Messages
Summary
| CVE | CVE-2026-34182 |
|---|---|
| State | PUBLISHED |
| Assigner | openssl |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-09 17:17:04 UTC |
| Updated | 2026-06-10 08:16:22 UTC |
| Description | Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises. Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message. In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message. An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with an attacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the real CEK, never consults the MAC field, and CMS_decrypt() returns success. If the application under attack responds to the attacker with any indicator showing success or failure of the decryption effort, it is possible for the attacker to use this as an oracle to obtain key equivalent functionality for the CEK used for the chosen recipient of the message. In another use case, an attacker can reduce the tag length of the chosen AEAD cipher for a given AuthEnvelopedData container to be a single byte long, allowing an attacker to brute force CMS decryption, producing an integrity bypass for applications that trust CMS_decrypt() to reject modified content. The FIPS modules are not affected by this issue. |
Risk And Classification
Problem Types: CWE-354 | CWE-354 CWE-354 Improper Validation of Integrity Check Value
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | OpenSSL | OpenSSL | affected 4.0.0 4.0.1 semver | Not specified |
| CNA | OpenSSL | OpenSSL | affected 3.6.0 3.6.3 semver | Not specified |
| CNA | OpenSSL | OpenSSL | affected 3.5.0 3.5.7 semver | Not specified |
| CNA | OpenSSL | OpenSSL | affected 3.4.0 3.4.6 semver | Not specified |
| CNA | OpenSSL | OpenSSL | affected 3.0.0 3.0.21 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/openssl/openssl/commit/7947e6a81eb8776802f159fb6762cb7fcf7e34c7 | [email protected] | github.com | |
| github.com/openssl/openssl/commit/03c1f4d45fb963aee7d5833390c507cd290182bc | [email protected] | github.com | |
| github.com/openssl/openssl/commit/439ed7d2c0962ce964482727264668bf277c333f | [email protected] | github.com | |
| openssl-library.org/news/secadv/20260609.txt | [email protected] | openssl-library.org | |
| github.com/openssl/openssl/commit/d2ca86bcd43e4f17d899f347101766b6107676e0 | [email protected] | github.com | |
| github.com/openssl/openssl/commit/9fd97f8cfdc2c0be214998de3b2b55c8edf6c7ac | [email protected] | github.com | |
| github.com/openssl/security/commit/03c1f4d45fb963aee7d5833390c507cd290182bc | MITRE | github.com | |
| github.com/openssl/security/commit/439ed7d2c0962ce964482727264668bf277c333f | MITRE | github.com | |
| github.com/openssl/security/commit/7947e6a81eb8776802f159fb6762cb7fcf7e34c7 | MITRE | github.com | |
| github.com/openssl/security/commit/9fd97f8cfdc2c0be214998de3b2b55c8edf6c7ac | MITRE | github.com | |
| github.com/openssl/security/commit/d2ca86bcd43e4f17d899f347101766b6107676e0 | MITRE | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Asim Viladi Oglu Manizada (en)
CNA: Alex Gaynor (Anthropic) (en)
CNA: Ying Dong (en)
CNA: Haiyang Huang (en)
CNA: Neil Horman (en)
There are currently no legacy QID mappings associated with this CVE.