CVE-2026-42845
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.
- SSVC automatable: yes - attacks can be scripted at scale
- ⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)
ATT&CK techniques
4Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
CAPEC attack patterns
8Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.