CVE-2026-89086: Ocaml Jose

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In the jose package before 0.11.0 for OCaml, library calls to validate an RSA signature only confirm that PKCS #1 decoding succeeds, and proceed to declare the signature valid without the required steps that involve the public key.

Affected products

• Ocaml Jose: before 0.11.0 (fixed in 0.11.0)

Published 2026-09-10. Last modified 2026-09-22.