Vulnerability in getgrav/grav-plugin-form (CVE-2026-42845)
Summary
Vulnerability in getgrav/grav-plugin-form (CVE-2026-42845). Risk of unauthorized operations or information disclosure. Exploitable via GET /upload. Mitigation: upgrade to 9.1.0 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42845 has been found in getgrav/grav-plugin-form.
Attackers can target a specific entry point like GET /upload over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade getgrav/grav-plugin-form to 9.1.0 or later.
If unsure, ask your IT team or search "getgrav/grav-plugin-form CVE-2026-42845" on the vendor's site.
CVE-2026-42845 (getgrav/grav-plugin-form) — CWE-20
Attack surface: GET /upload / POST /upload / filename / default.md
Patched: 9.1.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in getgrav/grav-plugin-form. Attackers reach the vulnerable code path via GET /upload.
Check the vendor advisory for the affected versions of getgrav/grav-plugin-form. Attack surface: GET /upload / POST /upload / filename / default.md.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 9.1.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /upload requests with malformed payloads or SQL meta-characters. Run grep -r 'getgrav/grav-plugin-form' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'getgrav/grav-plugin-form' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
getgrav/grav-plugin-formを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /upload' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /uploadへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade getgrav/grav-plugin-form to 9.1.0ステージング環境で 9.1.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /upload on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- web github.com