How severe is CVE-2026-42845?

No CVSS score has been assigned to CVE-2026-42845 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-42845?

CVE-2026-42845 affects the following packages: getgrav/grav-plugin-form (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-42845?

Update getgrav/grav-plugin-form to 9.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42845 is resolved across your whole dependency graph.

How do I detect CVE-2026-42845 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav-plugin-form. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-42845 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-42845?

O3 pinpoints whether CVE-2026-42845 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-42845 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-42845 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-42845 published, and has it been updated?

CVE-2026-42845 was published on May 11, 2026 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-42845

Fix: getgrav/grav-plugin-form@48bacc4

CVE-2026-42845 is a security vulnerability in getgrav/grav-plugin-form. O3 Security confirms whether CVE-2026-42845 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

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

Also known asGHSA-w4rc-p66m-x6qq

Published

May 11, 2026

Updated

Aug 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 7, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐘getgrav/grav-plugin-form

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`getgrav/grav-plugin-form`	all versions	9.1.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for getgrav/grav-plugin-form. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update getgrav/grav-plugin-form to 9.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42845 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42845 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-42845. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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 vulnera

O3 Security · Impact-Aware SCA

Is CVE-2026-42845 in your dependencies?

O3 detects CVE-2026-42845 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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