CVE-2026-59644: Legion of the Bouncy Castle BC-JAVA · Excessive Iteration
Affects Legion of the Bouncy Castle BC-JAVASource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 1.85 soon.
Data as of 31 Oct 2026, 08:20 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 42% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.85
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:AmberExploitation evidence
Disclosed: evidence found.
CVE published 3 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade BC-JAVA and bcmls to 1.85.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Legion of the Bouncy Castle Inc.BC-JAVA | Affected
| Fixed in
|
GitHubbcmlspkg:github/bcmlsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
CVE-2026-59644 is a high-severity vulnerability in Bouncy Castle for Java (BC-JAVA) versions before 1.85. It involves the MLS hash-ratchet honoring an arbitrary 32-bit generation counter from the sender, leading to excessive iteration. This flaw is categorized under CWE-834 (Excessive Iteration).