What is CVE-2026-34240?

CVE-2026-34240 is a high-severity vulnerability in Appsup-dart Jose, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.5/10. Published 2026-03-31.

How severe is CVE-2026-34240?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Appsup-dart Jose

CVE-2026-34240

JOSE is a Javascript Object Signing and Encryption (JOSE) library. Prior to version 0.3.5+1, a vulnerability in jose could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (…

EPSS: 0.000 (1.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Appsup-dart Jose — versions < 0.3.5+1

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97 (x_refsource_CONFIRM)
https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-34240?: CVE-2026-34240 is a high-severity vulnerability in Appsup-dart Jose, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.5/10. Published 2026-03-31.
How severe is CVE-2026-34240?: High severity. CVSS v3 base score is 7.5 out of 10.