CVE-2026-33204 HIGH

CVE-2026-33204: SimpleJWT has an Unauthenticated Denial of Service via JWE header tampering

Vendor Kelvinmo
Product simplejwt
Weakness CWE-400
Published March 20, 2026
Last update March 24, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

SimpleJWT is a simple JSON web token library written in PHP. Prior to version 1.1.1, an unauthenticated attacker can perform a Denial of Service via JWE header tampering when PBES2 algorithms are used. Applications that call JWE::decrypt() on attacker-controlled JWEs using PBES2 algorithms are affected. This issue has been patched in version 1.1.1.

Key dates

02Disclosure timeline

March 20, 2026 CVE published
March 24, 2026 Record updated