SimpleJWT has an Unauthenticated Denial of Service via JWE header tampering
Priority HIGH 72CWE-400Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-400.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.005 43rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial simplejwt (kelvinmo): 1.1.1kelvinmo/simplejwt (Packagist): 1.1.1Red Hat: 1 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| kelvinmo | simplejwt | before 1.1.1 | 1.1.1 | Patch available | CNA |
| — | kelvinmo/simplejwt (Packagist) | before 1.1.1 | 1.1.1 | Patch available | GHSA-xw36-67f8-339x |
- simplejwt Vendorkelvinmo Affected before 1.1.1 Fixed in 1.1.1 Patch available CNA
- kelvinmo/simplejwt (Packagist) Vendor— Affected before 1.1.1 Fixed in 1.1.1 Patch available GHSA-xw36-67f8-339x
Remediation
- Fix · CNA simplejwt (kelvinmo) Fixed in 1.1.1
- Fix · GHSA-xw36-67f8-339x kelvinmo/simplejwt (Packagist) Fixed in 1.1.1 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Ansible Automation Platform 2 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-33204
- 2026-10-03 Alias added: GHSA-xw36-67f8-339x
References
Sources
- CVE-2026-33204 · CVE Program
- CVE-2026-33204 · NVD
- FIRST EPSS
- GHSA-xw36-67f8-339x · GitHub Advisory Database · CC BY 4.0
- CVE-2026-33204 · Red Hat security data · CC BY 4.0
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