AIKIDO-2026-652915
bcprov-jdk18on is vulnerable to Improper Validation of Integrity Check Value
87
High Risk
This Affects:
bcprov-jdk18onTL;DR
In KCCMBlockCipher, the authentication tag computation does not bind the nonce when no additional authenticated data is supplied. Ciphertexts produced under different nonces can therefore collide in the MAC input for empty-AAD traffic. An attacker who can choose nonces may forge AEAD ciphertexts that verify under the same key. The fix includes the nonce in the MAC calculation even when AAD is absent.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you use KCCMBlockCipher with empty or absent AAD.
Background info
bcprov-jdk18on is vulnerable to Improper Validation of Integrity Check Value in versions 1.58.0 - 1.84.0.
How to fix this
Upgrade the org.bouncycastle provider library for your JDK target (bcprov-jdk18on, bcprov-jdk15to18 or bcprov-jdk14) to the patch version.
Links
Fix Commits
github.com/bcgit/bc-java/commit/697794413ebf7bc5e3fce609a707826ba52981afgithub.com/bcgit/bc-java/commit/7d79aa76e984da85f2a541cae8ba2ae56e1713bc
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SOC 2Compliant
ISO 27001Compliant