CVE-2026-34240

HIGH EPSS 3.0%
Published Mar 31, 20263mo ago · Modified Jun 17, 20262w ago
7.5 CVSS 3.1
High
Find Similar
Published Mar 31, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

Description

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 (jwk). The vulnerability exists because key selection could treat header-provided jwk as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key. Applications using affected versions for token verification are impacted. This issue has been patched in version 0.3.5+1. A workaround for this issue involves rejecting tokens where header jwk is present unless that jwk matches a key already present in the application's trusted key store.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity High
Availability None

Threat Intelligence

EPSS Exploit Probability
3.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-347

Affected Products 1

VendorProductVersionRange
appsup-dartjose* <0.3.5\+1

References 2

  • github.com https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d
    Patch
  • github.com https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97
    Vendor Advisory

Remediation

  • github.com https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d
    Patch