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Vulnerability record · CVE-2026-33204 · published 20 March 2026

CVE-2026-33204: Kelvinmo simplejwt uncontrolled resource consumption vulnerability

Kelvinmo · Simplejwt

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.

7.5 CVSS 3.1 High EPSS 0.54% · top 57.0% CWE-400 · Uncontrolled resource consumption
7.5CVSS 3.1 base score
0.54%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/kelvinmo/simplejwt/releases/tag/v1.1.1 ProductRelease Notes
https://github.com/kelvinmo/simplejwt/security/advisories/GHSA-xw36-67f8-339x ExploitVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-33204), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.