7.5

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

Awaiting analysis
AliasesUBUNTU-CVE-2026-5588DEBIAN-CVE-2026-5588CGA-26vh-cj23-x6c8
Published 15-04-2026Last modified 18-09-2026

Vulnerability summary

CVE-2026-5588 is a high (CVSS 7.5) vulnerability in legion of the bouncy castle inc. bc-java. EPSS estimates a 0.78% chance of exploitation in the next 30 days, higher than 55.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.78%
0%100%
Low · +0.09 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 9 · Related 2
OPENSUSE-SU-2026:10571-1RHSA-2026:18054RHSA-2026:18055RHSA-2026:53644RHSA-2026:53645RHSA-2026:53646

Timeline

  1. 15-04-2026
    PublishedVulnerability first disclosed.
  2. 18-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

10 scores · 7 sources · 2 versions

EPSS trend

Probability

0.78%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

Increase +0.09 pp

From 0.69% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard170 products
  • apache-nifi< 2.9.0-r0 | < 2.9.0-r3
  • apache-nifi-registry< 2.9.0-r1
  • apache-nifi-registry-toolkit< 2.9.0-r1
  • apache-pulsar-4.0< 4.0.9-r12
  • apache-pulsar-4.1All versions (No fix recorded)
Wolfi30 products
  • apache-nifi< 2.9.0-r0 | < 2.9.0-r3
  • apache-nifi-registry< 2.9.0-r1
  • apache-nifi-registry-toolkit< 2.9.0-r1
  • apache-pulsar-4.1All versions (No fix recorded)
  • apache-pulsar-4.2< 4.2.1-r0

2 vendors · 200 products · Showing 200 of 212

References

42 links
Show all 42 references