# CVE-2026-48062: CodeIgniter CodeIgniter4 file upload validation bypass in ext_in rule

Source: https://junglewise.ai/threats/cve-2026-48062-codeigniter-codeigniter4-file-upload-validation-bypass-in-ext-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-17. Updated: 2026-07-17  
License: CC BY 4.0 with a link back

CVE-2026-48062 · Severity: critical · CVSS 9.8 · Published 2026-07-17

CodeIgniter is a popular framework used by developers to build PHP websites. A security flaw in its file upload validation system allows attackers to bypass file type restrictions by disguising malicious scripts (like PHP shells) as harmless images. If a website using this framework allows users to upload files to a public folder, an attacker could take full control of the web server and access sensitive data.

Technologies: [CodeIgniter Foundation CodeIgniter4](https://junglewise.ai/threats/technologies/codeigniter4), [codeigniter4/framework (Packagist)](https://junglewise.ai/threats/technologies/codeigniter4-framework). Vendors: [CodeIgniter Foundation](https://junglewise.ai/threats/vendors/codeigniter-foundation), [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2026-48062 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48062 being exploited in the wild.

**How severe is CVE-2026-48062?** Critical severity, with a CVSS score of 9.8, published 17 July 2026.

**Which products and versions are affected?** CodeIgniter Foundation CodeIgniter4 < 4.7.2, < 4.7.3; codeigniter4/framework (Packagist) < 4.7.2, ECOSYSTEM:introduced=0,fixed=4.7.3.

**Is there a fix for CVE-2026-48062?** Yes. codeigniter4/framework (Packagist): upgrade to 4.7.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-48062 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-48062?** Check whether you run CodeIgniter Foundation CodeIgniter4 or codeigniter4/framework (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- codeigniter4/framework (Packagist): upgrade to 4.7.3 or later

  ```sh
  composer require codeigniter4/framework:^4.7.3
  ```


## Technical details

A vulnerability exists in CodeIgniter 4's `ext_in` upload validation rule within `system/Validation/StrictRules/FileRules.php`. The rule incorrectly validates the MIME-derived guessed extension rather than the actual client-provided filename extension. An attacker can exploit this by uploading a file with a dangerous extension (e.g., .php) containing content that mimics a safe MIME type (e.g., a GIF header). If the application saves the file using its original name in a web-accessible directory, the attacker can execute arbitrary code. This issue is resolved in version 4.7.3 by ensuring the rule validates the client-provided extension.

## Affected products

- CodeIgniter Foundation CodeIgniter4 < 4.7.3

## Identifiers

- CVE-2026-48062
- GHSA-2gr4-ppc7-7mhx

## Timeline

- 2026-05-20: advisory: GitHub Security Advisory published
- 2026-05-22: patched: Version 4.7.3 released
- 2026-07-17: disclosed: CVE-2026-48062 published to NVD

## References

- [https://github.com/codeigniter4/CodeIgniter4/commit/29299349e7d232e9532767c7cefaed30957309be](https://github.com/codeigniter4/CodeIgniter4/commit/29299349e7d232e9532767c7cefaed30957309be)
- [https://github.com/codeigniter4/CodeIgniter4/releases/tag/v4.7.3](https://github.com/codeigniter4/CodeIgniter4/releases/tag/v4.7.3)
- [https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-2gr4-ppc7-7mhx](https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-2gr4-ppc7-7mhx)

## Related threats

- [CodeIgniter CodeIgniter4 unrestricted file upload in is_image and mime_in rules](https://junglewise.ai/threats/cve-2026-63223-codeigniter-codeigniter4-unrestricted-file-upload-in-is-image-and)
- [CodeIgniter Path Traversal in UploadedFile move method](https://junglewise.ai/threats/cve-2026-63222-codeigniter-path-traversal-in-uploadedfile-move-method)
- [CodeIgniter SQL injection in Query Builder deleteBatch](https://junglewise.ai/threats/cve-2026-63221-codeigniter-sql-injection-in-query-builder-deletebatch)
- [CodeIgniter CodeIgniter4 header spoofing in IncomingRequest::isSecure](https://junglewise.ai/threats/cve-2026-63220-codeigniter-codeigniter4-header-spoofing-in-incomingrequest)
- [CodeIgniter4's ImageMagick Handler has Command Injection Vulnerability](https://junglewise.ai/threats/cve-2025-54418-codeigniter4-s-imagemagick-handler-has-command-injection)