VulnerabilityAnalyzed

CVE-2026-8763

In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI.

CRITICAL 9.3EPSS 0.43%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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).

CVSS 4.0: 9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.43% probability · 36th percentile
CISA KEV: Not listed
Weakness: CWE-295
Affected: bouncycastle/bc-java · bouncycastle/bouncy castle for java lts · bouncycastle/fips java api
Source: 91579145-5d7b-4cc5-b925-a0262ff19630

References

https://github.com/bcgit/bc-java/commit/2c28b253a44681fbbc562561eab6ad383d2ae558Patch
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%908763Third Party Advisory, Patch

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.