CVE-2026-63223: File Upload RCE (CVSS 9.8)

Description

CodeIgniter is a PHP full-stack web framework. Prior to 4.7.4, the is_image and mime_in upload validation rules do not independently enforce a safe client filename extension, allowing a remote attacker to upload executable content when an application preserves the client filename and stores uploads in a web-accessible script-enabled directory. Applications are impacted when they validate uploads using is_image or mime_in without an independent safe extension check (such as ext_in on patched versions), save uploaded files using the client-supplied filename, and place uploads in a web-accessible directory where PHP files can execute. This issue is fixed in version 4.7.4.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0049

Probability of exploitation

0.40%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-434 Unrestricted Upload

References

Other References

https://github.com/codeigniter4/CodeIgniter4/commit/b6e9a4fa1dca2df3d3f261bdf61532df8c6420aa https://github.com/codeigniter4/CodeIgniter4/releases/tag/v4.7.4 https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-mmj4-63m4-r6h5

Frequently Asked Questions

What is CVE-2026-63223? +

CodeIgniter is a PHP full-stack web framework. Prior to 4.7.4, the is_image and mime_in upload validation rules do not independently enforce a safe client filename extension, allowing a remote attacker to upload executable content when an application preserves the client filename and stores uploads in a web-accessible script-enabled directory. Applications are impacted when they validate uploads using is_image or mime_in without an independent safe extension check (such as ext_in on patched versions), save uploaded files using the client-supplied filename, and place uploads in a web-accessible directory where PHP files can execute. This issue is fixed in version 4.7.4. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-63223? +

CVE-2026-63223 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0049, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63223? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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