CVE-2026-63571: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-cwfr-988g-hf77
Share
CWE-347
Published
Advisory Summary

CVE-2026-63571 is a HIGH security vulnerability vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not verify, or incorrectly verifies, the cryptographic signature for data.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-63571 at a Glance

CVE Identifier CVE-2026-63571
GHSA Identifier GHSA-cwfr-988g-hf77
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-63571

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-63571, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Improper verification of cryptographic signature in the attribute certificate path validator (PkixAttrCertPathValidator, also used by PkixAttrCertPathBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker to have a forged X.509 attribute certificate accepted as valid, and so obtain whatever roles or privileges an application grants on the strength of its attributes, via an attribute certificate that names a trusted attribute authority as its issuer but was not signed by it, because the RFC 3281 validation steps check the holder and issuer certification paths, validity period, extensions and revocation status but never verify the attribute certificate's signature with the issuer's public key. Only applications that use these classes to validate attribute certificates are affected.

References

NVD — CVE-2026-63571 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63571
Security Fix Commit FIX COMMIT
https://github.com/bcgit/bc-csharp/commit/c08f65e1ed7b92a10776220ed9c047f47c264725
GitHub Advisory / Wiki ADVISORY
https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63571

Frequently Asked Questions

What is CVE-2026-63571?
CVE-2026-63571 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-347: Improper Verification of Cryptographic Signature.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-63571?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-63571?
CVE-2026-63571 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check Maven dependencies for CVE-2026-63571?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-cwfr-988g-hf77",
  "modified" : "2026-10-02T09:31:19Z",
  "published" : "2026-10-02T09:31:19Z",
  "aliases" : [ "CVE-2026-63571" ],
  "details" : "Improper verification of cryptographic signature in the attribute certificate path validator (PkixAttrCertPathValidator, also used by PkixAttrCertPathBuilder) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote attacker to have a forged X.509 attribute certificate accepted as valid, and so obtain whatever roles or privileges an application grants on the strength of its attributes, via an attribute certificate that names a trusted attribute authority as its issuer but was not signed by it, because the RFC 3281 validation steps check the holder and issuer certification paths, validity period, extensions and revocation status but never verify the attribute certificate's signature with the issuer's public key. Only applications that use these classes to validate attribute certificates are affected.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-63571"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-csharp/commit/c08f65e1ed7b92a10776220ed9c047f47c264725"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63571"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-02T08:17:01Z"
  }
}