Vulnerability · Published Jul 15, 2026 · Assigned by VulnCheck

CVE-2026-61873Grav before 9.1.8 Arbitrary File Write via Twig-Processed Filename

High 8.1

In plain English

A high-severity security flaw in grav from getgrav. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.3%top 76.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Grav before 9.1.8 contains an arbitrary file write vulnerability in the Form plugin's process.save.filename parameter, which is validated against path traversal before Twig processing but never re-validated after rendering. Attackers can submit form data containing path traversal sequences that are processed through Twig templates, allowing them to write arbitrary files including PHP webshells to the web root or other sensitive directories.

Affected products (as reported)

Vendor	Product	Versions
getgrav	grav	0 – before 9.1.8

Weakness: CWE-73 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

References

GitHub Security Advisory (GHSA-q532-mvx7-42qg) vendor-advisory
VulnCheck Advisory: Grav before 9.1.8 Arbitrary File Write via Twig-Processed Filename third-party-advisory