Skip to content
Fencer Vulns
critical 9.1

CVE-2026-89086 json

JOSE: missing RSA signature verification

published 2026-09-10 59 d ago modified 2026-11-06 2 d ago also EUVD-2026-75708 , OSEC-2026-19

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • opam jose 0.11.0
  • OCaml jose 0.11.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
59 d ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
OSV 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
opam jose
<0.11.0
0.11.0

Affected products

  • OCaml jose

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.