What is CVE-2026-89086?

CVE-2026-89086 is a critical-severity vulnerability in Ocaml Jose, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-09-10.

How severe is CVE-2026-89086?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Ocaml Jose

CVE-2026-89086

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.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Ocaml Jose

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

cve@mitre.org
cve@mitre.org

Frequently asked questions

What is CVE-2026-89086?: CVE-2026-89086 is a critical-severity vulnerability in Ocaml Jose, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-09-10.
How severe is CVE-2026-89086?: Critical severity. CVSS v3 base score is 9.1 out of 10.