SB2026052048 - Improper access control in Form plugin for Grav CMS

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Main Vulnerability Database SB2026052048

SB2026052048 - Improper access control in Form plugin for Grav CMS

Published: May 20, 2026

Security Bulletin ID SB2026052048
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper access control (CVE-ID: CVE-2026-42845)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to escalate privileges.

The vulnerability exists due to improper access control in the Form plugin file upload handler and page content file handling when processing file uploads with a POST-supplied filename override. A remote attacker can upload a specially crafted markdown file with a chosen filename to overwrite a page's .md content file and escalate privileges.

Exploitation requires a form upload field that permits text files, such as using accept: ['*'], with uploads directed to the page directory via the default self@ destination.


Remediation

Install update from vendor's website.

References