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CVE-2026-33204

HIGHCVSS 7.5/10EPSS 0.48%

Last modified

CVE-2026-33204 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.48% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
0.48%

37.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
KelvinmoSimplejwt< 1.1.1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2026-33204?
CVE-2026-33204 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.48% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33204?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33204?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST