CVE-2026-12803

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CVSS 4.0

8.7 high

EPSS

<1%p6

Published

Aug 3, 2026 (Aug 3, 2026)

Modified

Sep 2, 2026

Description

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.

Vendors: bouncycastle
Products: bc-java, bouncy castle for java lts
Weakness: CWE-354
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber

NVD CVE.org GitHub PoCs EPSS (0.2%)

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