Vulnerability details
CVE-2026-59638
Legion of the Bouncy Castle BC-FJALegion of the Bouncy Castle BC-JAVALegion of the Bouncy Castle BC-LTS-JAVA
JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
CVSS 4.0
9.3Critical
Official description
In Bouncy Castle for Java before 1.85, JSSE hostname verifier CN-fallback enabled by default despite documented opt-in. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bctls-fips 1.0.24 (1.0.X series), 2.0.24 (2.0.X series) and 2.1.24 (2.1.X series).
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.3Critical | 4.0 | CVEProject cvelistV5 (CNA) (bcorg) | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Legion of the Bouncy Castle Inc. | BC-FJA | 1.0.7 ≤ v < 1.0.24 | CVEProject cvelistV5 (CNA) |
| Legion of the Bouncy Castle Inc. | BC-FJA | 2.0.0 ≤ v < 2.0.24 | CVEProject cvelistV5 (CNA) |
| Legion of the Bouncy Castle Inc. | BC-FJA | 2.1.0 ≤ v < 2.1.24 | CVEProject cvelistV5 (CNA) |
| Legion of the Bouncy Castle Inc. | BC-JAVA | 1.61 ≤ v < 1.85 | CVEProject cvelistV5 (CNA) |
| Legion of the Bouncy Castle Inc. | BC-LTS-JAVA | 2.73.0 ≤ v < 2.73.12 | CVEProject cvelistV5 (CNA) |
References and advisories
3
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Details
- Published
- 2026-08-03
- Last updated
- 2026-08-03
- State
- Published
- Assigner (CNA)
- bcorg
Exploit prediction (EPSS)
0.34%
Probability of exploitation in 30 days
28.2%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-297Improper Validation of Certificate with Host Mismatch