CVE-2026-59651: CWE-326 Inadequate Encryption Strength in Legion of the Bouncy Castle Inc. BC-JAVA
CVE-2026-59651 is a vulnerability in Bouncy Castle for Java (BC-JAVA) affecting versions before 1.85 and LTS versions from 2.73.0 up to but not including 2.73.12. The issue involves the BKS keystore accepting a legacy version that uses a 16-bit integrity MAC key, which is considered inadequate encryption strength. This weakness could potentially undermine the integrity protection of the keystore data.
AI Analysis
Technical Summary
The vulnerability CVE-2026-59651 in Legion of the Bouncy Castle Inc.'s BC-JAVA product involves the acceptance of a legacy BKS keystore version that uses a 16-bit integrity MAC key. This key length is insufficient for strong cryptographic integrity verification, classified under CWE-326 (Inadequate Encryption Strength). The affected versions are all BC-JAVA versions prior to 1.85 and LTS versions from 2.73.0 up to but excluding 2.73.12. No official remediation level or patch information is provided in the available data.
Potential Impact
The use of a 16-bit integrity MAC key in the affected BKS keystore versions weakens the cryptographic integrity protection, potentially allowing attackers to tamper with keystore contents without detection. This undermines the security guarantees of the keystore, which could lead to compromised confidentiality or integrity of stored cryptographic keys or credentials. However, no known exploits in the wild have been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should monitor official Bouncy Castle communications for updates or patches addressing this issue. Until a fix is available, avoid using legacy BKS keystore versions with 16-bit MAC keys if possible.
CVE-2026-59651: CWE-326 Inadequate Encryption Strength in Legion of the Bouncy Castle Inc. BC-JAVA
Description
CVE-2026-59651 is a vulnerability in Bouncy Castle for Java (BC-JAVA) affecting versions before 1.85 and LTS versions from 2.73.0 up to but not including 2.73.12. The issue involves the BKS keystore accepting a legacy version that uses a 16-bit integrity MAC key, which is considered inadequate encryption strength. This weakness could potentially undermine the integrity protection of the keystore data.
CVSS v4.0
Score 7.1high
Affected software
Legion of the Bouncy Castle Inc.
BC-JAVA
Legion of the Bouncy Castle Inc.
BC-LTS-JAVA
pkg:github/bcprov-lts8onRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-59651 in Legion of the Bouncy Castle Inc.'s BC-JAVA product involves the acceptance of a legacy BKS keystore version that uses a 16-bit integrity MAC key. This key length is insufficient for strong cryptographic integrity verification, classified under CWE-326 (Inadequate Encryption Strength). The affected versions are all BC-JAVA versions prior to 1.85 and LTS versions from 2.73.0 up to but excluding 2.73.12. No official remediation level or patch information is provided in the available data.
Potential Impact
The use of a 16-bit integrity MAC key in the affected BKS keystore versions weakens the cryptographic integrity protection, potentially allowing attackers to tamper with keystore contents without detection. This undermines the security guarantees of the keystore, which could lead to compromised confidentiality or integrity of stored cryptographic keys or credentials. However, no known exploits in the wild have been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should monitor official Bouncy Castle communications for updates or patches addressing this issue. Until a fix is available, avoid using legacy BKS keystore versions with 16-bit MAC keys if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- bcorg
- Date Reserved
- 2026-07-06T07:09:01.524Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a6fe8f3bf32cb7a34b623c4
Added to database: 08/03/2026, 01:03:47 UTC
Last enriched: 08/10/2026, 15:26:40 UTC
Last updated: 09/15/2026, 13:00:04 UTC
Views: 97
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