TI-2026-31054 Aliases CVE-2026-42845 GHSA-w4rc-p66m-x6qq

Grav: Anonymous Page Content Overwrite via Form File Upload filename Override

HIGH 73CWE-73Published 2026-05-11 · Updated 2026-05-12

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: None · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00741 54th percentileScored 2026-11-07

Fix Fixed grav-plugin-form (getgrav): 9.1.0getgrav/grav-plugin-form (Packagist): 9.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
getgrav	grav-plugin-form	before 9.1.0	9.1.0	Patch available	CNA
—	getgrav/grav-plugin-form (Packagist)	before 9.1.0	9.1.0	Patch available	GHSA-w4rc-p66m-x6qq

grav-plugin-form Vendorgetgrav Affected before 9.1.0 Fixed in 9.1.0 Patch available CNA
getgrav/grav-plugin-form (Packagist) Vendor— Affected before 9.1.0 Fixed in 9.1.0 Patch available GHSA-w4rc-p66m-x6qq

Remediation

Fix · CNA grav-plugin-form (getgrav) Fixed in 9.1.0
Fix · GHSA-w4rc-p66m-x6qq getgrav/grav-plugin-form (Packagist) Fixed in 9.1.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-42845
2026-10-03 Alias added: GHSA-w4rc-p66m-x6qq
2026-10-27 EPSS moved to the 50th–90th percentile

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-42845

Other 3

TI-2026-30893 Grav: Privilege Escalation via Missing Server-Side Validation of groups/access CVSS 3.1CRITICAL 9.4
TI-2025-28971 Cross Site Scripting vulnerability in grav v.1.7.48 and before allows an attacker to… CVSS 3.1CRITICAL 9.8
TI-2021-04523 Unauthenticated Arbitrary YAML Write/Update leads to Code Execution CVSS 3.1CRITICAL 9.8
TI-2026-50940 Grav CMS before 2.0.16 Origin Validation Bypass via Referer CVSS 4.0CRITICAL 9.3
TI-2026-46446 Grav before 2.0.7 Remote Code Execution via Blueprint dynamicData CVSS 4.0CRITICAL 9.3
TI-2021-22428 GravCMS 1.10.7 - Arbitrary YAML Write/Update (Unauthenticated) (2) CVSS 4.0CRITICAL 9.3

See all 228 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences