JWE decryption and forgery via undersized authentication tags
Published Aug 8, 2025 · Updated Aug 8, 2025
Improper integrity validation in JWT ruby-jwe 1.1.0 and earlier allows remote attackers to decrypt or forge encrypted JWEs. During AES-GCM decryption, setup_cipher assigns an attacker-controlled authentication tag to OpenSSL without first enforcing the required 16-byte length. Short tags can be brute-forced through observable parsing differences, exposing plaintext, enabling arbitrary decrypted values, and recovering the GHASH key even when a JWE uses another content-encryption algorithm.
Summary
What happened
Improper integrity validation in JWT ruby-jwe 1.1.0 and earlier allows remote attackers to decrypt or forge encrypted JWEs. During AES-GCM decryption, setup_cipher assigns an attacker-controlled authentication tag to OpenSSL without first enforcing the required 16-byte length. Short tags can be brute-forced through observable parsing differences, exposing plaintext, enabling arbitrary decrypted values, and recovering the GHASH key even when a JWE uses another content-encryption algorithm.
The record
- CVE
- CVE-2025-54887
- Published
- Aug 8, 2025
- Updated
- Aug 8, 2025
- Vendor
- JWT
- Product
- ruby-jwe
- Classifications
- CWE-354
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 8, 2025CVE publishedPublication date reported by the CVE source.
- Aug 8, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 1.1.1
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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