codeigniter4/framework security advisory

CVE-2026-63223: CodeIgniter: Uploaded file extension validation bypass in is_image and mime_in rules

CVE-2026-63223 is a critical-severity arbitrary file upload vulnerability in the PHP package codeigniter4/framework (CVSS 9.8), published 31 July 2026. It is fixed in 4.7.4; earlier versions are affected. It can be exploited without an account.

critical 9.8 published 2026-07-31 · updated 2026-09-08

Affected versions: < 4.7.4
Fixed in: 4.7.4
Newest release: 4.7.6
Severity: Critical · CVSS 9.8
Type: Arbitrary file upload
CWE-434
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Is your codeigniter4/framework version affected?

Run composer show codeigniter4/framework in your project, then enter the version. We check it against this and every other known codeigniter4/framework advisory.

Who can exploit CVE-2026-63223

Access: No account. Anyone who can send a request to an app that uses the affected code.

CVSS vector (scored by GitHub): CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Your app is only exposed if it uses the affected part of codeigniter4/framework. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-63223 in codeigniter4/framework

Find the installed version: composer show codeigniter4/framework. If you never required it yourself, composer why codeigniter4/framework shows which package pulls it in.
Update it: composer update codeigniter4/framework --with-all-dependencies. You need 4.7.4 or newer.
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "codeigniter4/framework": "^4.7.4" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-63223.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for arbitrary file upload issues while the upgrade waits. None of it replaces the fix.

Rename uploaded files on the server instead of keeping the name the user sent, and allow only the extensions you expect.
Store uploads outside the web root, or turn off PHP execution in the upload folder.
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-63223 advisory

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.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-63223. Advisory title: “CodeIgniter: Uploaded file extension validation bypass in is_image and mime_in rules”.

References

GitHub advisory GHSA-mmj4-63m4-r6h5 github.com
Fix commit b6e9a4f github.com
Release v4.7.4 github.com

Other codeigniter4/framework advisories

high CVE-2026-63222: CodeIgniter: Path traversal in UploadedFile::move() when using client-provided filenames 2026-08-07
critical CVE-2026-63221: CodeIgniter: SQL injection in Query Builder deleteBatch() when used with where() conditions 2026-08-07
medium CVE-2026-63220: CodeIgniter: Spoofable forwarded HTTPS headers in IncomingRequest::isSecure() 2026-08-07
critical CVE-2026-48062: CodeIgniter4 has a validation bypass when uploading file extensions via ext_in rule 2026-06-11
critical CVE-2025-54418: CodeIgniter4's ImageMagick Handler has Command Injection Vulnerability 2025-07-28
medium CVE-2025-24013: Missing validation of header name and value in codeigniter4/framework 2025-01-21

Need help patching or upgrading? Laskyr does PHP and Laravel security fixes and upgrades. Tell us what you run and we reply with a plan and a price.

Ask about a fix

Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.