SEPTEMBER 20, 2026
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Case File

CVE-2026-12803

HIGH · CVSS 8.7 EPSS 0.18% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-03 · Last synced 2026-09-02

CyberRota Analysis

AI-Generated

Bouncy Castle for Java versions prior to 1.85 and LTS versions before 2.73.12 are vulnerable due to a flaw in the KCCMBlockCipher MAC, which fails to bind the nonce when the Additional Authenticated Data (AAD) is absent, potentially allowing for cross-nonce AEAD forgery attacks. This vulnerability could lead to unauthorized data manipulation or decryption in applications relying on this cryptographic library. Developers and organizations using affected versions should prioritize updating to mitigate the risk of exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links
github.com ↗ github.com ↗ github.com ↗

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-12803
Severity
HIGH
CVSS
8.7
EPSS
0.18%
Java

Original NVD 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.