Bug#1134386: bouncycastle: CVE-2026-5598: timing channel in FrodoKEM

[James Montgomery]

Package: bouncycastle
Version: 1.80-3
Severity: important
Tags: security upstream
User: debian-security at lists.debian.org
Usertags: CVE-2026-5598

Dear Maintainer,

The following vulnerability was published for bouncycastle.

CVE-2026-5598[1]:
| Covert timing channel vulnerability in Legion of the Bouncy Castle Inc.
| BC-JAVA core on all (core modules). Non-constant time comparisons risk
| private key leakage in FrodoKEM.

Upstream lists BC 1.71 through 1.83 as affected and BC 1.84 as fixed[2].
The current Debian package in stable/testing/unstable is 1.80-3, which is
within that affected range.

The upstream fix appears to be:

  https://github.com/bcgit/bc-java/commit/94abbd56413dfdac651fd878bc60253871ef5e87

[1] https://www.cve.org/CVERecord?id=CVE-2026-5598
[2] https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905598

Regards,
James