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Vulnerability record · CVE-2021-33199 · published 12 August 2021

CVE-2021-33199: Expressionengine improper input validation vulnerability

Expressionengine · Expressionengine

In Expression Engine before 6.0.3, addonIcon in Addons/file/mod.file.php relies on the untrusted input value of input->get('file') instead of the fixed file names of icon.png and icon.svg.

9.8 CVSS 3.1 Critical EPSS 1.4% · top 29.3% CWE-20 · Improper input validation
9.8CVSS 3.1 base score, v2 7.5
1.4%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

In Expression Engine before 6.0.3, addonIcon in Addons/file/mod.file.php relies on the untrusted input value of input->get('file') instead of the fixed file names of icon.png and icon.svg.

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

Affected products

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

References

LinkTags
https://github.com/ExpressionEngine/ExpressionEngine/compare/6.0.1...6.0.3#diff-17bcb23e5666fc2dccb79c7133e9eeb701847f67 PatchThird Party Advisory
https://github.com/ExpressionEngine/ExpressionEngine/releases/tag/6.0.3 Release NotesThird Party Advisory
https://github.com/ExpressionEngine/ExpressionEngine/compare/6.0.1...6.0.3#diff-17bcb23e5666fc2dccb79c7133e9eeb701847f67 PatchThird Party Advisory
https://github.com/ExpressionEngine/ExpressionEngine/releases/tag/6.0.3 Release NotesThird Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-33199), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.