Vulnerability in Bouncycastle Bc-Java
CVE-2026-8763
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).
Vulnerability class: Improper Certificate Validation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (37.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Bouncycastle Bc-Java
- Bouncycastle Bouncy Castle For Java Lts
- Bouncycastle Fips Java API
- Legion Of The Bouncy Castle Inc. Bc-Fja — versions 1.0.0, 2.0.0, 2.1.0
- Legion Of The Bouncy Castle Inc. Bc-Java — versions 0
- Legion Of The Bouncy Castle Inc. Bc-Lts-Java — versions 2.73.0
Weakness classification (CWE)
References
- 91579145-5d7b-4cc5-b925-a0262ff19630 (Patch, patch)
- 91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory)
- 91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-8763?
- CVE-2026-8763 is a critical-severity vulnerability in Bouncycastle Bc-Java, classified under Improper Certificate Validation. CVSS score: 9.1/10. Published 2026-08-03.
- How severe is CVE-2026-8763?
- Critical severity. CVSS v3 base score is 9.1 out of 10.