Resource exhaustion in Kelvinmo Simplejwt
CVE-2026-33204
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
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:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.001
Affected products
- Kelvinmo Simplejwt — versions < 1.1.1
Weakness classification (CWE)
References
- github.com/kelvinmo/simplejwt/security/advisories/GHSA-xw36-67f8-339x (Exploit, Vendor Advisory)
- github.com/kelvinmo/simplejwt/releases/tag/v1.1.1 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-33204?
- CVE-2026-33204 is a high-severity vulnerability in Kelvinmo Simplejwt, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-03-20.
- How severe is CVE-2026-33204?
- High severity. CVSS v3 base score is 7.5 out of 10.