CVE-2026-48062 is a critical-severity (CVSS 9.8) Unrestricted File Upload vulnerability in codeigniter4/framework. A fix is available for codeigniter4/framework — see the affected versions and patch details below.
CodeIgniter: Uploaded file extension validation bypass in `ext_in` rule
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-48062.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-48062 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 389,824 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
codeigniter4/frameworkReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The ext_in upload validation rule 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_into validate the uploaded filename extension, - save uploaded files using the original client filename:
$file->move($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. The default application does not expose such an upload endpoint.
Patches
Upgrade to v4.7.3 or later.
Workarounds
- Save uploads outside the public web root, preferably under
writable/uploads - Use
$file->store()or$file->move($path, $file->getRandomName())instead of preserving the original filename - Disable script execution in any public upload directory
- Manually verify the client filename extension before moving the file
- Reject files when
$file->getClientExtension()is not in the allowed list or does not match$file->guessExtension()
Resources
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | codeigniter4/framework | all versions | 4.7.3composer require codeigniter4/framework:^4.7.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for codeigniter4/framework, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update codeigniter4/framework to 4.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48062 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Frequently Asked Questions
Is CVE-2026-48062 in your dependencies?
Find it across Packagist, including transitive dependencies.