Arbitrary Markdown writes via unvalidated language code
Published Sep 4, 2026 · Updated Sep 4, 2026
Path traversal in the Grav Admin Plugin before 1.10.55 allows remote authenticated users to write arbitrary Markdown files. AdminController::taskSaveas passes the unvalidated data[lang] POST value into determineFilenameIncludingLanguage(), which appends it to the page directory before File::save() and Page::save() write attacker-controlled content. Exploitation requires admin.pages.create permission and a valid admin nonce, but no super-admin role or non-default configuration, and the write remains limited to .md files.
Summary
What happened
Path traversal in the Grav Admin Plugin before 1.10.55 allows remote authenticated users to write arbitrary Markdown files. AdminController::taskSaveas passes the unvalidated data[lang] POST value into determineFilenameIncludingLanguage(), which appends it to the page directory before File::save() and Page::save() write attacker-controlled content. Exploitation requires admin.pages.create permission and a valid admin nonce, but no super-admin role or non-default configuration, and the write remains limited to .md files.
The record
- CVE
- CVE-2026-85603
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- GetGrav
- Product
- Grav
- Classifications
- CWE-73, T1105
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.10.55
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- GHSA-h9g9-73c3-23c9 embedded Save As reproductionfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo