CVE-2026-42845 Details
Description
The form plugin for Grav adds the ability to create and use forms. Prior to 9.1.0 , there is an unauthenticated page-content overwrite via file upload (GHSA-w4rc-p66m-x6qq). Public form uploads now strip path components from the POST-supplied filename and hard-block page-content extensions (`md`, `yaml`, `yml`, `json`, `twig`, `ini`) regardless of the configurable dangerous-extensions list. A permissive `accept` policy combined with the default `destination: self@` could otherwise let an attacker overwrite the page's own `.md` and pivot to super-admin via a `process: save` action. This vulnerability is fixed in 9.1.0.
A vulnerability in the Grav Form plugin prior to version 9.1.0 allows for unauthenticated page-content overwrites through file uploads. The vulnerability arises because the upload handler accepts a POST-supplied filename that can override the original uploaded filename, bypassing certain extension restrictions. This flaw could enable an attacker to upload a file that replaces a page's content file, such as 'form.md', and potentially escalate privileges to super-admin by exploiting the form processing actions.
Users are advised to update the Grav Form plugin to version 9.1.0 or later, where this vulnerability has been fixed. Additionally, sensitive page-content filenames should be blocked at upload by adding them to the global 'security.uploads_dangerous_extensions' list.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 11, 2026CISA-ADP
Assessed May 12, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq | CISA-ADP | AdvisoryRemedyVendor |
| https://github.com/getgrav/grav-plugin-form/commit/48bacc4187e1cff815000e526d5ca2878484867f | [email protected] | Source CodeVendor |
| https://github.com/getgrav/grav/security/advisories/GHSA-w4rc-p66m-x6qq | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-73 | External Control of File Name or Path | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Grav | < 9.1.0 (semver) |
CPE
Remediation
| |
| Grav Form | All versions |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 12, 2026 | CVE Modified | CISA-ADP |
| May 11, 2026 | New CVE Received | [email protected] |