CVE-2026-59641: CWE-345 Insufficient Verification of Data Authenticity in Legion of the Bouncy Castle Inc. BC-JAVA
CVE-2026-59641 is a high-severity vulnerability in Legion of the Bouncy Castle Inc.'s BC-JAVA library. The issue involves insufficient verification of data authenticity in the S/MIME validator, which trusts the signer-asserted signingTime during path validation. This affects Bouncy Castle for Java versions before 1.85, versions from 2.73.0 up to but not including 2.73.12, and certain FIPS versions prior to specified releases.
AI Analysis
Technical Summary
The vulnerability CVE-2026-59641 in BC-JAVA arises from the S/MIME validator trusting the signer-asserted signingTime for certificate path validation. This insufficient verification of data authenticity (CWE-345) can lead to incorrect validation outcomes. The affected versions include Bouncy Castle for Java before 1.85, Bouncy Castle for Java LTS versions from 2.73.0 up to 2.73.12, and Bouncy Castle for Java FIPS versions before bcmail-fips and bcjmail-fips 1.0.7 (1.0.X series), 2.0.7 (2.0.X series), and 2.1.7 (2.1.X series). The CVSS 4.0 base score is 8.7, indicating a high severity with network attack vector, no privileges required, no user interaction, and high impact on integrity.
Potential Impact
The vulnerability allows an attacker to exploit the insufficient verification of the signingTime attribute in S/MIME signatures, potentially causing the certificate path validation to trust incorrect or manipulated signing times. This can undermine the integrity of signature validation processes relying on BC-JAVA, possibly allowing forged or invalid signatures to be accepted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Users should monitor the Legion of the Bouncy Castle Inc. advisories for updates and apply any forthcoming patches promptly. Until a fix is available, consider avoiding use of affected versions or implementing additional verification controls outside of BC-JAVA's S/MIME validator if feasible.
CVE-2026-59641: CWE-345 Insufficient Verification of Data Authenticity in Legion of the Bouncy Castle Inc. BC-JAVA
Description
CVE-2026-59641 is a high-severity vulnerability in Legion of the Bouncy Castle Inc.'s BC-JAVA library. The issue involves insufficient verification of data authenticity in the S/MIME validator, which trusts the signer-asserted signingTime during path validation. This affects Bouncy Castle for Java versions before 1.85, versions from 2.73.0 up to but not including 2.73.12, and certain FIPS versions prior to specified releases.
CVSS v4.0
Score 8.7high
Affected software
pkg:github/bcmail-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-2026-59641 in BC-JAVA arises from the S/MIME validator trusting the signer-asserted signingTime for certificate path validation. This insufficient verification of data authenticity (CWE-345) can lead to incorrect validation outcomes. The affected versions include Bouncy Castle for Java before 1.85, Bouncy Castle for Java LTS versions from 2.73.0 up to 2.73.12, and Bouncy Castle for Java FIPS versions before bcmail-fips and bcjmail-fips 1.0.7 (1.0.X series), 2.0.7 (2.0.X series), and 2.1.7 (2.1.X series). The CVSS 4.0 base score is 8.7, indicating a high severity with network attack vector, no privileges required, no user interaction, and high impact on integrity.
Potential Impact
The vulnerability allows an attacker to exploit the insufficient verification of the signingTime attribute in S/MIME signatures, potentially causing the certificate path validation to trust incorrect or manipulated signing times. This can undermine the integrity of signature validation processes relying on BC-JAVA, possibly allowing forged or invalid signatures to be accepted.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch information is provided in the available data. Users should monitor the Legion of the Bouncy Castle Inc. advisories for updates and apply any forthcoming patches promptly. Until a fix is available, consider avoiding use of affected versions or implementing additional verification controls outside of BC-JAVA's S/MIME validator if feasible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- bcorg
- Date Reserved
- 2026-07-06T06:58:29.263Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a6fe8f1bf32cb7a34b61c9a
Added to database: 08/03/2026, 01:03:45 UTC
Last enriched: 08/03/2026, 01:19:37 UTC
Last updated: 08/03/2026, 01:52:25 UTC
Views: 3
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