CVE-2026-55887.5HighCWE-327

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

Legion of the Bouncy Castle Inc. · BC-JAVA

Vendor fix available · Affected: Legion of the Bouncy Castle Inc. BC-JAVA · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.8%probability of exploitation in the next 30 days

57th percentile

050100

Higher than 57% of scored CVEs

7.5HighCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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 products3

From the CVE record. A product or version that is not listed is unknown, not unaffected.

Legion of the Bouncy Castle Inc. · BC-JAVAfrom 1.67 before 1.80.2; from 1.81 before 1.81.1; from 1.82 before 1.84
Legion of the Bouncy Castle Inc. · BCPKIX-FIPSfrom 2.0.6 before 2.0.11; from 2.1.7 before 2.1.11
Legion of the Bouncy Castle Inc. · BCPIX-LTSfrom 2.73.7 before 2.73.11

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Use of a Broken or Risky Cryptographic Algorithm · Cryptography
Vendor: Legion of the Bouncy Castle Inc.
Published: April 2026
Band: Unlikely (under 1%), April 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-5588 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.

References

18 more references are in the CVE record.