Message forgery via skipped empty-ciphertext tag computation
Published Jun 9, 2026 · Updated Jun 9, 2026
Missing authentication in affected OpenSSL releases allows attackers to forge empty AES-SIV or AES-GCM-SIV messages with arbitrary AAD. The provider defers expected-tag computation until a ciphertext update; when no update occurs, EVP_DecryptFinal_ex compares an all-zero supplied tag against the unchanged all-zero expected tag. Exploitation requires a custom application protocol using these EVP ciphers and skipping the ciphertext update for empty input; AES-SIV additionally requires reuse of a decryption context without resetting the key.
Summary
What happened
Missing authentication in affected OpenSSL releases allows attackers to forge empty AES-SIV or AES-GCM-SIV messages with arbitrary AAD. The provider defers expected-tag computation until a ciphertext update; when no update occurs, EVP_DecryptFinal_ex compares an all-zero supplied tag against the unchanged all-zero expected tag. Exploitation requires a custom application protocol using these EVP ciphers and skipping the ciphertext update for empty input; AES-SIV additionally requires reuse of a decryption context without resetting the key.
The record
- CVE
- CVE-2026-45446
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- OpenSSL Project
- Product
- OpenSSL
- Classifications
- CWE-325, CAPEC-68
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.0.0 <3.0.21
- Affected versionversion=3.4.0 <3.4.6
- Affected versionversion=3.5.0 <3.5.7
- Affected versionversion=3.6.0 <3.6.3
- Affected versionversion=4.0.0 <4.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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