CVE-2026-61873

Grav before 9.1.8 Arbitrary File Write via Twig-Processed Filename

HIGH
8.1
CVSS Score
Published: July 15, 2026 at 11:25 AM UTC
Updated: October 24, 2026 at 09:10 PM UTC
1 product affected across 1 vendorGrav

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Severity
HIGH8.1
Exploit prediction
EPSS 0.3%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

90%
0 ≤ v < 9.1.80
Vendor states this is fixed in 9.1.8 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-73

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