Plaintext disclosure via GOST CTR counter wrap
Published Apr 15, 2026 · Updated Apr 15, 2026
Cryptographic weakness in Bouncy Castle Java allows attackers to infer plaintext relationships from repeated GOST CTR keystream. G3413CTRBlockCipher increments only the counter's final byte, so it wraps after 255 blocks and reuses the same keystream. Exploitation requires more than 255 blocks under the same key and IV plus access to two resulting ciphertexts, exposing the XOR relationship between their plaintexts.
Summary
What happened
Cryptographic weakness in Bouncy Castle Java allows attackers to infer plaintext relationships from repeated GOST CTR keystream. G3413CTRBlockCipher increments only the counter's final byte, so it wraps after 255 blocks and reuses the same keystream. Exploitation requires more than 255 blocks under the same key and IV plus access to two resulting ciphertexts, exposing the XOR relationship between their plaintexts.
The record
- CVE
- CVE-2025-14813
- Published
- Apr 15, 2026
- Updated
- Apr 15, 2026
- Vendor
- Legion of the Bouncy Castle Inc.
- Product
- Bouncy Castle Java
- Classifications
- CWE-323
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 15, 2026CVE publishedPublication date reported by the CVE source.
- Apr 15, 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?
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- Affected versionversion=1.59 <1.84
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
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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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