CVE-2026-5588 — PKIX draft CompositeVerifier accepts empty signature sequence as valid.

Description (CNA)

Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules), Legion of the Bouncy Castle Inc. BCPKIX-FIPS bcpkix on All (pkix modules), Legion of the Bouncy Castle Inc. BCPIX-LTS bcpkix on All (pkix modules). This vulnerability is associated with program files JcaContentVerifierProviderBuilder.Java, JcaContentVerfierProviderBuilder.Java. This issue affects BC-JAVA: from 1.67 before 1.80.2, from 1.81 before 1.81.1, from 1.82 before 1.84; BCPKIX-FIPS: from 2.0.6 before 2.0.11, from 2.1.7 before 2.1.11; BCPIX-LTS: from 2.73.7 before 2.73.11.

Affected (CNA)

Vendor / product	Versions
Legion of the Bouncy Castle Inc. / BC-JAVA	affected 1.67 before 1.80.2; affected 1.81 before 1.81.1; affected 1.82 before 1.84
Legion of the Bouncy Castle Inc. / BCPKIX-FIPS	affected 2.0.6 before 2.0.11; affected 2.1.7 before 2.1.11
Legion of the Bouncy Castle Inc. / BCPIX-LTS	affected 2.73.7 before 2.73.11

CWE

CWE-327

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix. The PKIX draft `CompositeVerifier` implementation improperly accepts an empty signature sequence as a valid cryptographic signature. This issue allows a remote attacker to bypass signature verification mechanisms, potentially compromising the authenticity and integrity of data.