9.3

CVE-2026-8763: bouncycastle bc-java Improper Certificate Validation

CVSS: 9.3v4.0CriticalAnalyzed
AliasesUBUNTU-CVE-2026-8763DEBIAN-CVE-2026-8763CGA-232w-mxqf-pc2c
Published 03-08-2026Last modified 05-10-2026
Open JSON

Vulnerability summary

CVE-2026-8763 is a critical (CVSS 9.3) Improper Certificate Validation vulnerability in bouncycastle bc-java. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.8% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.3/10
010
Critical · v4.0 (CVE.org)
EPSS score
0.43%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 5 · Related 6
OPENSUSE-SU-2026:11445-1OPENSUSE-SU-2026:21538-1SUSE-SU-2026:23127-1SUSE-SU-2026:23150-1SUSE-SU-2026:3559-1CGA-3JR9-VHCV-J8P6

Timeline

  1. 03-08-2026
    PublishedVulnerability first disclosed.
  2. 05-10-2026
    Last modifiedVulnerability information updated.

Description

In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).

CVSS metrics

10 scores · 7 sources · 2 versions

EPSS trend

Probability

0.43%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

0.00 pp

From 0.43% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.43%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard142 products
  • airbyte-platform-workload-launcher< 2.0.0-r8
  • apache-nifi-2.11All versions (No fix recorded)
  • apache-nifi-2.12< 2.12.0-r1
  • apache-nifi-registry-2.11< 2.11.0-r4
  • apache-nifi-registry-2.12< 2.12.0-r1
Wolfi19 products
  • apache-pulsar-4.2< 4.2.4-r5
  • druid< 37.0.0-r57
  • keycloak-26.5All versions (No fix recorded)
  • keycloak-26.5-iamguarded-compatAll versions (No fix recorded)
  • keycloak-26.6< 26.6.7-r1
Org.bouncycastle4 products
  • bc-fips< 1.0.2.7 | ≥ 2.0.0, < 2.0.2 | ≥ 2.1.0, < 2.1.3
  • bcprov-jdk15to18< 1.85
  • bcprov-jdk18on< 1.85
  • bcprov-lts8on< 2.73.12
Bouncycastle3 products
Legion of the bouncy castle inc.3 products
Debian1 product
  • bouncycastleAll versions (No fix recorded) | < 1.86-1
Ubuntu1 product
  • bouncycastleAll versions (No fix recorded)

7 vendors · 173 products

References

14 links
Show all 14 references