Vulnerability in Bouncycastle Bc-Java
CVE-2026-59640
In Bouncy Castle for Java before 1.85, OpenPGP CFB quick-check oracle active on symmetric/session-key paths. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpg-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (28.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Bouncycastle Bc-Java
- Bouncycastle Bcpg-Fips
- Bouncycastle Bouncy Castle For Java Lts
- Legion Of The Bouncy Castle Inc. Bc-Fja — versions 1.0.0, 2.0.0, 2.1.0
- Legion Of The Bouncy Castle Inc. Bc-Java — versions 0
- Legion Of The Bouncy Castle Inc. Bc-Lts-Java — versions 2.73.0
Weakness classification (CWE)
References
- 91579145-5d7b-4cc5-b925-a0262ff19630 (Patch, patch)
- 91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory)
- 91579145-5d7b-4cc5-b925-a0262ff19630 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-59640?
- CVE-2026-59640 is a medium-severity vulnerability in Bouncycastle Bc-Java, classified under Observable Discrepancy. CVSS score: 5.3/10. Published 2026-08-03.
- How severe is CVE-2026-59640?
- Medium severity. CVSS v3 base score is 5.3 out of 10.