Vulnerability · Published Aug 3, 2026 · Assigned by bcorg
CVE-2026-8763Name Constraints bypass via trailing dot in rfc822Name and URI
Critical 9.3
In plain English
A critical-severity improper certificate validation in BC-FJA from Legion of the Bouncy Castle Inc.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | bouncycastle | no fix listed | DEBIAN-CVE-2026-8763 |
| Debian:13 | bouncycastle | no fix listed | DEBIAN-CVE-2026-8763 |
| Debian:14 | bouncycastle | 1.86-1 | DEBIAN-CVE-2026-8763 |
| Maven | org.bouncycastle:bc-fips | 2.0.2 | GHSA-9pwp-9qqc-pr26 |
| Maven | org.bouncycastle:bc-fips | 1.0.2.7 | GHSA-9pwp-9qqc-pr26 |
| Maven | org.bouncycastle:bc-fips | 2.1.3 | GHSA-9pwp-9qqc-pr26 |
| Maven | org.bouncycastle:bcprov-jdk15to18 | 1.85 | GHSA-9pwp-9qqc-pr26 |
| Maven | org.bouncycastle:bcprov-jdk18on | 1.85 | GHSA-9pwp-9qqc-pr26 |
| Maven | org.bouncycastle:bcprov-lts8on | 2.73.12 | GHSA-9pwp-9qqc-pr26 |
| Ubuntu:26.04:LTS | bouncycastle | no fix listed | UBUNTU-CVE-2026-8763 |
| Ubuntu:26.10 | bouncycastle | no fix listed | UBUNTU-CVE-2026-8763 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-JAVA | 0 – before 1.85 |
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 – before 2.73.12 |
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.0 – before 1.0.2.72.0.0 – before 2.0.22.1.0 – before 2.1.3 |
Weakness: CWE-295 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber