CVE-2026-33204
Denial of Service in SimpleJWT via JWE PBES2 Header Tampering
Publication date: 2026-03-20
Last updated on: 2026-04-10
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| kelvinmo | simplejwt | to 1.1.1 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-400 | The product does not properly control the allocation and maintenance of a limited resource. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in SimpleJWT, a PHP library for JSON web tokens. Before version 1.1.1, an unauthenticated attacker could cause a Denial of Service (DoS) by tampering with the JWE header when PBES2 algorithms are used. Specifically, applications that call the JWE::decrypt() function on attacker-controlled JWEs using PBES2 algorithms are vulnerable.
How can this vulnerability impact me? :
The vulnerability can lead to a Denial of Service (DoS) attack, meaning an attacker can disrupt the normal functioning of an application by exploiting the JWE header tampering issue. This can cause the application to become unavailable or unresponsive when processing maliciously crafted JSON web tokens.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade the SimpleJWT library to version 1.1.1 or later, where the issue has been patched.
Additionally, avoid calling JWE::decrypt() on attacker-controlled JWEs using PBES2 algorithms until the upgrade is applied.