Bouncy Castle for Java GOST 28147 CTR mode reuses keystream after 255 blocks
The GOST 28147-2015 CTR mode implementation (`G3413CTRBlockCipher`) in the Legion of the Bouncy Castle BC-JAVA `bcprov` core module only increments the final byte of the counter, so the counter wraps after 255 blocks and the keystream is reused. Reusing CTR keystream allows an attacker who can observe two ciphertexts produced with the same key/IV to recover the XOR of the plaintexts, breaking confidentiality. Affects BC-JAVA from 1.59 before 1.84 (with backported fixes in 1.80.2 and 1.81.1).
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-14813US | —OT elevated | — | ||
: Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcprov on all (core modules).
This vulnerability is associated with p… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:11720WEB
- https://access.redhat.com/errata/RHSA-2026:11721WEB
- https://access.redhat.com/errata/RHSA-2026:13631WEB
- https://access.redhat.com/errata/RHSA-2026:14272WEB
- https://access.redhat.com/errata/RHSA-2026:14276WEB
- https://access.redhat.com/errata/RHSA-2026:17668WEB
- https://access.redhat.com/errata/RHSA-2026:18054WEB
- https://access.redhat.com/errata/RHSA-2026:18055WEB
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