PT-2026-67016 · Legion Of The Bouncy Castle · Bc-Java+1

CVE-2026-12803 · Published 2026-08-03 · Updated 2026-08-03

Mitre

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber

In Bouncy Castle for Java before 1.85, KCCMBlockCipher MAC does not bind nonce when AAD is absent (cross-nonce AEAD forgery). This issue also affects Bouncy Castle for Java LTS before 2.73.12.

Exploit

Fix

Weakness Enumeration

CWE-354

Related Identifiers

CVE-2026-12803

Affected Products

Bc-Java

Bc-Lts-Java

References · 4

• 🔥 https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9012803 · Exploit
• https://github.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc · Patch
• https://github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981af · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-12803 · Security Note