CVE-2026-5588

MEDIUM

PKIX draft CompositeVerifier accepts empty signature sequence as valid.

Title source: cna

Description

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.

References (2)

Core 2

Core References

vendor-advisory

https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588

Patch patch

https://github.com/bcgit/bc-java/commit/656bae0dbd9b1521f840521ff786e78749fe3057

View Patch ZIP pw:eip

Scores

CVSS v4 6.3

EPSS 0.0026

EPSS Percentile 17.0%

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-327

Status published

Products (15)

Legion of the Bouncy Castle Inc./BC-JAVA 1.49 - 1.84

Legion of the Bouncy Castle Inc./BC-JAVA 1.67 - 1.80.2

Legion of the Bouncy Castle Inc./BC-JAVA 1.67 - 1.84

Legion of the Bouncy Castle Inc./BC-JAVA 1.81 - 1.81.1

Legion of the Bouncy Castle Inc./BC-JAVA 1.82 - 1.84

Legion of the Bouncy Castle Inc./BCPIX-LTS 2.73.7 - 2.73.11

Legion of the Bouncy Castle Inc./BCPKIX-FIPS 2.0.6 - 2.0.11

Legion of the Bouncy Castle Inc./BCPKIX-FIPS 2.1.7 - 2.1.11

org.bouncycastle/bcpkix-debug-jdk14 1.49 - 1.84Maven

org.bouncycastle/bcpkix-debug-jdk15to18 1.49 - 1.84Maven

... and 5 more

Published Apr 15, 2026

Tracked Since Apr 15, 2026