CVE-2026-5588

PKIX draft CompositeVerifier accepts empty signature sequence as valid.

Published Apr 15, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-wg6q-6289-32hp Bouncy Castle Crypto Package For Java: Use of a Broken or Risky Cryptographic Algorithm vulnerability in bcpkix modules
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:11720 cve-icon
https://access.redhat.com/errata/RHSA-2026:11721 cve-icon
https://access.redhat.com/errata/RHSA-2026:13631 cve-icon
https://access.redhat.com/errata/RHSA-2026:14272 cve-icon
https://access.redhat.com/errata/RHSA-2026:14276 cve-icon
https://access.redhat.com/errata/RHSA-2026:17668 cve-icon
https://access.redhat.com/errata/RHSA-2026:18054 cve-icon
https://access.redhat.com/errata/RHSA-2026:18055 cve-icon
https://access.redhat.com/errata/RHSA-2026:18059 cve-icon
https://access.redhat.com/errata/RHSA-2026:21772 cve-icon
https://access.redhat.com/errata/RHSA-2026:53644 cve-icon
https://access.redhat.com/errata/RHSA-2026:53645 cve-icon
https://access.redhat.com/errata/RHSA-2026:53646 cve-icon
https://access.redhat.com/errata/RHSA-2026:60239 cve-icon
https://access.redhat.com/errata/RHSA-2026:60246 cve-icon
https://access.redhat.com/errata/RHSA-2026:60247 cve-icon
https://access.redhat.com/errata/RHSA-2026:60248 cve-icon
https://access.redhat.com/errata/RHSA-2026:60249 cve-icon
https://access.redhat.com/errata/RHSA-2026:60250 cve-icon
https://access.redhat.com/errata/RHSA-2026:60251 cve-icon
https://access.redhat.com/errata/RHSA-2026:60252 cve-icon
https://access.redhat.com/errata/RHSA-2026:60254 cve-icon
https://access.redhat.com/errata/RHSA-2026:60256 cve-icon
https://access.redhat.com/errata/RHSA-2026:60259 cve-icon
https://access.redhat.com/errata/RHSA-2026:66488 cve-icon
https://access.redhat.com/security/cve/CVE-2026-5588 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2458634 cve-icon
https://github.com/bcgit/bc-java/commit/656bae0dbd9b1521f840521ff786e78749fe3057 cve-icon cve-icon
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-5588 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5588.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-5588 cve-icon
History
Type Values Removed Values Added
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 1.84; 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. 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.
Type Values Removed Values Added
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). This vulnerability is associated with program files JcaContentVerifierProviderBuilder.Java. This issue affects BC-JAVA: from 1.67 before 1.84; BCPKIX-FIPS: from 2.0.6 before 2.0.11, from 2.1.7 before 2.1.11. 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 1.84; 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.
Type Values Removed Values Added
Weaknesses CWE-347
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

threat_severity

Important

Type Values Removed Values Added
Description Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).This issue affects BC-JAVA: from 1.67 before 1.84. 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). This vulnerability is associated with program files JcaContentVerifierProviderBuilder.Java. This issue affects BC-JAVA: from 1.67 before 1.84; BCPKIX-FIPS: from 2.0.6 before 2.0.11, from 2.1.7 before 2.1.11.
Metrics cvssV4_0

{'score': 6.3, 'vector': '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/U:Green'}

cvssV4_0

{'score': 6.3, 'vector': '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/U:Amber'}

Type Values Removed Values Added
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. Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).This issue affects BC-JAVA: from 1.67 before 1.84.
References
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV4_0

{'score': 10, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}

cvssV4_0

{'score': 6.3, 'vector': '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/U:Green'}

Type Values Removed Values Added
First Time appeared Bouncycastle
Bouncycastle bc-java
Vendors & Products Bouncycastle
Bouncycastle bc-java
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title PKIX draft CompositeVerifier accepts empty signature sequence as valid.
Weaknesses CWE-327
References
Metrics cvssV4_0

{'score': 10, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
bcorg
Published
Updated
Sep 18, 2026, 12:04 PM
Reserved
Apr 4, 2026, 11:50 PM
Status
Awaiting Analysis
Published
Apr 15, 2026, 10:16 AM
Modified
Oct 26, 2026, 9:10 PM
Severity
Important
Public date
Apr 15, 2026, 9:06 AM