PKIX draft CompositeVerifier accepts empty signature sequence as valid.

Summary

CVECVE-2026-5588
StatePUBLISHED
Assignerbcorg
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-15 10:16:49 UTC
Updated2026-04-15 17:17:06 UTC
Description: Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules). PKIX draft CompositeVerifier accepts empty signature sequence as valid. This issue affects BC-JAVA: from 1.49 before 1.84.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from 91579145-5d7b-4cc5-b925-a0262ff19630

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:Green

Problem Types: CWE-327 | CWE-327 CWE-327: Use of a Broken or Risky Cryptographic Algorithm


VersionSourceTypeScoreSeverityVector
4.091579145-5d7b-4cc5-b925-a0262ff19630Secondary6.3MEDIUMCVSS: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/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/U:Green

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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:Green

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Legion Of The Bouncy Castle Inc. BC-JAVA affected 1.67 1.84 maven all

References

ReferenceSourceLinkTags
github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588 91579145-5d7b-4cc5-b925-a0262ff19630 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Nicholas Carlini using Claude, Anthropic (en)

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