CVE-2026-8763: Bouncycastle Bc-Java

Critical severity, CVSS 9.1. EPSS: 0.4% chance of exploitation in the next 30 days.

In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).

Affected products

• Bouncycastle Bc-Java: before 1.85 (fixed in 1.85)
• Bouncycastle Bouncy Castle For Java LTS: up to and including 2.73.11
• Bouncycastle Fips Java API: from 1.0.0, before 1.0.2.7 (fixed in 1.0.2.7); from 2.0.0, before 2.0.2 (fixed in 2.0.2); from 2.1.0, before 2.1.3 (fixed in 2.1.3)

Published 2026-08-03. Last modified 2026-09-02.