Vulnerability in Bouncycastle Bc-Java

CVE-2026-12852

In Bouncy Castle for Java before 1.85, MLS wire decoder allocates attacker-declared opaque length before bounds check.

EPSS: 0.003 (23.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Bouncycastle Bc-java
Legion Of The Bouncy Castle Inc. Bc-java — versions 1.73

Weakness classification (CWE)

CWE-789

References

91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory)
91579145-5d7b-4cc5-b925-a0262ff19630 (Patch, patch)
91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2026-12852?: CVE-2026-12852 is a high-severity vulnerability in Bouncycastle Bc-Java, classified under CWE-789. CVSS score: 7.5/10. Published 2026-08-03.
How severe is CVE-2026-12852?: High severity. CVSS v3 base score is 7.5 out of 10.