GHSA-MMJ4-63M4-R6H5
Vulnerability from github – Published: 2026-08-07 18:24 – Updated: 2026-08-07 18:24
VLAI
Summary
CodeIgniter: Uploaded file extension validation bypass in `is_image` and `mime_in` rules
Details
Impact
This is an unsafe file upload validation vulnerability that can lead to remote code execution in vulnerable application configurations.
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
- place uploads in a web-accessible directory where PHP files can execute
Patches
Upgrade to v4.7.4 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 client filename. - Disable script execution in any public upload directory.
- Manually verify the client filename extension before moving the file.
- For image uploads, reject files when
$file->getClientExtension()is not an allowed image extension. - For exact MIME-type validation, reject files when
$file->getClientExtension()does not match$file->guessExtension().
Severity
9.8 (Critical)
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "codeigniter4/framework"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.7.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-63223"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-07T18:24:21Z",
"nvd_published_at": "2026-07-31T06:16:32Z",
"severity": "CRITICAL"
},
"details": "### Impact\nThis is an unsafe file upload validation vulnerability that can lead to remote code execution in vulnerable application configurations.\n\nApplications are impacted when they:\n- validate uploads using `is_image` or `mime_in` without an independent safe extension check, such as `ext_in` on patched versions\n- save uploaded files using the client-supplied filename\n- place uploads in a web-accessible directory where PHP files can execute\n\n### Patches\nUpgrade to v4.7.4 or later.\n\n### Workarounds\n- Save uploads outside the public web root, preferably under `writable/uploads`.\n- Use `$file-\u003estore()` or `$file-\u003emove($path, $file-\u003egetRandomName())` instead of preserving the original client filename.\n- Disable script execution in any public upload directory.\n- Manually verify the client filename extension before moving the file.\n- For image uploads, reject files when `$file-\u003egetClientExtension()` is not an allowed image extension.\n- For exact MIME-type validation, reject files when `$file-\u003egetClientExtension()` does not match `$file-\u003eguessExtension()`.",
"id": "GHSA-mmj4-63m4-r6h5",
"modified": "2026-08-07T18:24:21Z",
"published": "2026-08-07T18:24:21Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-mmj4-63m4-r6h5"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63223"
},
{
"type": "WEB",
"url": "https://github.com/codeigniter4/CodeIgniter4/commit/b6e9a4fa1dca2df3d3f261bdf61532df8c6420aa"
},
{
"type": "PACKAGE",
"url": "https://github.com/codeigniter4/CodeIgniter4"
},
{
"type": "WEB",
"url": "https://github.com/codeigniter4/CodeIgniter4/releases/tag/v4.7.4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "CodeIgniter: Uploaded file extension validation bypass in `is_image` and `mime_in` rules"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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