CVE-2026-61457
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe Grav API plugin (getgrav/grav-plugin-api) before 1.0.3 contains a file upload extension bypass in the API media controller. HandlesMediaUploads::validateFileExtension() inspects only the final file extension via pathinfo($filename, PATHINFO_EXTENSION), so a user with api.media.write permission can upload a file with a double extension such as shell.php.jpg to bypass the dangerous extensions blocklist. The web server may then execute the file as PHP, resulting in remote code execution.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Grav CMS API plugin before version 1.0.3 has a file upload extension bypass in the media controller. The validateFileExtension() method uses pathinfo() to check only the final extension, allowing attackers with api.media.write permission to bypass the dangerous extensions blocklist using double extensions like shell.php.jpg. If the web server executes the uploaded file as PHP, this results in remote code execution.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check API plugin versionLocate the API plugin in the Grav installation (typically in user/plugins/api/ or vendor/getgrav/grav-plugin-api/) and read the plugin.yaml or composer.json file to find the installed version numberAffected if The installed version is lower than 1.0.3
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Identify users with api.media.write permissionReview the permissions configuration in user/config/permissions.yaml or the user account YAML files to see which users or groups are granted the api.media.write permissionAffected if Any untrusted user account has the api.media.write permission enabled
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Inspect validateFileExtension methodExamine the media controller file (typically in the API plugin's controller directory) and locate the validateFileExtension() method to verify if it only uses pathinfo() for single-extension validationAffected if The method uses pathinfo() without checking for multiple/embedded extensions
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Verify upload directory PHP execution policyCheck the web server configuration (Apache .htaccess, Nginx config, or IIS URL Rewrite rules) to determine if PHP execution is allowed in directories where uploaded files are storedAffected if The web server permits execution of PHP files in the upload directory paths used by the API plugin
You are affected if the API plugin version is below 1.0.3, any untrusted user has api.media.write permission, and the web server can execute uploaded PHP files in the upload directory.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade the getgrav/grav-plugin-api to version 1.0.3 or later, which should implement proper multi-extension validation. Until patched, revoke api.media.write permission from untrusted users and configure the web server to prevent execution of uploaded files.
grav-plugin-api version 1.0.3 or later
- Check the current version of the grav-plugin-api by examining the plugin's version file or composer.json in the project dependencies
- Upgrade the grav-plugin-api to version 1.0.3 or later using Composer: composer update getgrav/grav-plugin-api or by updating the version constraint in composer.json to ^1.0.3
- After upgrading, clear any caching (grav cache:clear) to ensure the new version is loaded
- Verify the upgrade was successful by checking the installed version matches 1.0.3 or higher
- Test that the file upload validation now properly validates all extensions in a double-extension filename (e.g., shell.php.jpg should be rejected)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-61457 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-61457 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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