codeigniter4/framework security advisory

CVE-2026-48062: CodeIgniter4 has a validation bypass when uploading file extensions via ext_in rule

CVE-2026-48062 is a critical-severity remote code execution vulnerability in the PHP package codeigniter4/framework (CVSS 9.8), published 17 July 2026. It is fixed in 4.7.2; earlier versions are affected. It can be exploited without an account.

critical 9.8 published 2026-07-17 · updated 2026-07-23

Affected versions: < 4.7.2
Fixed in: 4.7.2
Newest release: 4.7.6
Severity: Critical · CVSS 9.8
Type: Remote code execution
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-2026-48062

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-2026-48062 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 4.7.2 or newer.
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "codeigniter4/framework": "^4.7.2" 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-2026-48062.
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 remote code execution issues while the upgrade waits. None of it replaces the fix.

Never pass user-controlled data to unserialize() or to template rendering, and restrict who can edit templates or settings.
Put a web application firewall in front of the app and watch for new PHP files or admin users.
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-48062 advisory

CodeIgniter is a PHP full-stack web framework. Prior to 4.7.3, the ext_in upload validation rule in system/Validation/StrictRules/FileRules.php checked the MIME-derived guessed extension instead of the client-provided filename extension. As a result, an uploaded file named shell.php containing GIF-like content could pass validation such as uploaded[avatar]|is_image[avatar]|mime_in[avatar,image/gif]|ext_in[avatar,gif] because the detected MIME type maps to gif, even though the uploaded filename extension is php. Applications are impacted if they accept user-controlled uploads, rely on ext_in to validate the uploaded filename extension, save uploaded files using the original client filename with $file->move($path), store uploads in a web-accessible directory, and allow PHP or other executable files to run from that directory. In those conditions, this may lead to arbitrary code execution. This issue is fixed in version 4.7.3.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-48062. Advisory title: “CodeIgniter4 has a validation bypass when uploading file extensions via ext_in rule”.

References

GitHub advisory GHSA-2gr4-ppc7-7mhx github.com
Fix commit 2929934 github.com
Release v4.7.3 github.com

Other codeigniter4/framework advisories

critical CVE-2026-63223: CodeIgniter: Uploaded file extension validation bypass in is_image and mime_in rules 2026-08-07
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-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.

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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.