AIKIDO-2026-38955
bcprov-jdk18on is vulnerable to Improper Verification of Cryptographic Signature
87
High Risk
This Affects:
bcprov-jdk18onTL;DR
RSADigestSigner on the PKCS#1 NULL-omitted DigestInfo path compares the recovered digest while skipping the last two hash bytes. Signatures that mismatch only in those trailing bytes can still verify successfully. Callers that accept RSA PKCS#1 signatures through this path may treat forged or mutated signatures as valid. The fix compares the full digest including the final two bytes.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and you verify RSA PKCS#1 signatures through RSADigestSigner on the NULL-omitted DigestInfo path.
Background info
bcprov-jdk18on is vulnerable to Improper Verification of Cryptographic Signature in versions 0.0.1 - 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
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SOC 2Compliant
ISO 27001Compliant