Review reviewHigh

CVE-2026-59644

Legion of the Bouncy Castle Inc. BC-JAVA

In Bouncy Castle for Java before 1.85, MLS hash-ratchet honours arbitrary 32-bit generation counter from sender.

PRIORITY ASSESSMENT

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 8.7

In Bouncy Castle for Java before 1.85, MLS hash-ratchet honours arbitrary 32-bit generation counter from sender.

Confirm exposure before applying a vendor-supported change.

1
Identify
Confirm that Legion of the Bouncy Castle Inc. BC-JAVA and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

CVSS vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber
CWE: CWE-834