Bouncycastle: In Bouncy Castle for Java before 1.85, CMS AuthenticatedData content not bound to MAC when authAttrs present. (CVE-2026-59642)
Description
A vulnerability in Bouncy Castle for Java before version 1.85 causes the CMS AuthenticatedData content to not be bound to the MAC when authenticated attributes are present. This affects multiple Bouncy Castle Java versions including LTS and FIPS variants prior to specified fixed versions. The issue can lead to integrity violations of authenticated data.
CVSS v3.1
Score 7.5high
Affected software
pkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/xenialpkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/focalpkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/bouncycastle?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/bouncycastle?arch=source&distro=stonkingpkg:deb/ubuntu/bouncycastle?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59642 describes a cryptographic vulnerability in Bouncy Castle for Java versions prior to 1.85, as well as LTS versions before 2.73.12 and FIPS versions before bcpkix-fips 1.0.12, 2.0.12, and 2.1.12. The flaw is that when authenticated attributes (authAttrs) are present in CMS AuthenticatedData, the content is not properly bound to the Message Authentication Code (MAC). This can undermine the integrity guarantees of the CMS AuthenticatedData structure, potentially allowing an attacker to tamper with the content without detection.
Potential Impact
The vulnerability impacts the integrity of CMS AuthenticatedData by allowing the content to be unbound from the MAC when authenticated attributes are present. This could enable attackers to modify data without invalidating the MAC, leading to integrity violations. There is no indication of confidentiality or availability impact. No known exploits are reported in the wild.
Mitigation Recommendations
A fix is available in Bouncy Castle for Java version 1.85 and later, in LTS version 2.73.12 and later, and in FIPS versions bcpkix-fips 1.0.12, 2.0.12, and 2.1.12 and later. Users should upgrade to these fixed versions to remediate the vulnerability. No vendor advisory was provided to contradict this; therefore, upgrading is recommended.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-59642
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f5da2cdf04f65666324e
Added to database: 10/17/2026, 22:25:30 UTC
Last enriched: 10/18/2026, 00:30:20 UTC
Last updated: 10/18/2026, 00:30:20 UTC
Views: 2
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