CVE-2026-59644: MLS hash-ratchet honours arbitrary 32-bit generation counter from sender

High severity · published Aug 3, 2026

CVE-2026-59644

MLS hash-ratchet honours arbitrary 32-bit generation counter from sender

7.5

CVSS

0.5%

EPSS

On KEV

Description

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)0.5% · higher than 42% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

BC-JAVA · Legion of the Bouncy Castle Inc.

1.73 before 1.85 · source: vendor, NVD

Affected product

BC-JAVA

Legion of the Bouncy Castle Inc.

All BC-JAVA CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-59644

CVE.org

https://www.cve.org/CVERecord?id=CVE-2026-59644

Patch

https://github.com/bcgit/bc-java/commit/610d8757d855afe197df0de6d831cb75c81e3b9f

Third Party Advisory

https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059644