Intel

AIKIDO-2026-550297

bcpg-jdk18on is vulnerable to Improper Validation of Integrity Check Value

CVE-2026-12817Published Aug 5, 2026
August 5, 2026

87

CVE Score

High

Improper Validation of Integrity Check Value

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TL;DR

Bouncy Castle's OpenPGP AEAD decryption omits verification of the final authentication tag when the ciphertext ends on a chunk boundary. A tampered message can have its trailing plaintext chunk silently stripped or altered and still be accepted as authentic. This breaks the AEAD integrity guarantee and can also expose message contents. The fix verifies the final tag unconditionally before signalling end of stream in both the Bc and Jce decryptors.

How do I fix this?

Upgrade the org.bouncycastle:bcpg-jdk18on library to the patch version.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and your application performs OpenPGP AEAD (SEIPDv2/v5) decryption on externally supplied messages.

Versions

1.74 - 1.84

Fixed in 1.85

Background info

bcpg-jdk18on is vulnerable to Improper Validation of Integrity Check Value in versions 1.74 - 1.84.

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