Privilege Escalation in Plainpad (CVE-2026-42562)
Summary
Vulnerability in Plainpad (CVE-2026-42562). Confidential information can be exposed externally. Exploitable via PUT /api.php/v1/users/{id}..
Original description
The description as published by the source.
Plainpad is a self hosted note taking app. Prior to version 1.1.1, Plainpad allows a low-privilege authenticated user to self-escalate to administrator by submitting admin=true in PUT /api.php/v1/users/{id}. The endpoint directly persists the admin attribute from user input, and the escalated account can immediately access admin-only routes. This issue has been patched in version 1.1.1.
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-2026-42562 has been found in Plainpad.
Attackers can target a specific entry point like PUT /api.php/v1/users/{id}. over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Plainpad CVE-2026-42562" on the vendor's site.
CVE-2026-42562 (Plainpad) — CWE-269 / CVSS v3 8.3
Attack vector: remote (network-reachable) / no user interaction
Attack surface: PUT /api.php/v1/users/{id}.
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-269) exists in Plainpad. Attackers reach the vulnerable code path via PUT /api.php/v1/users/{id}..
Check the vendor advisory for the affected versions of Plainpad. Attack surface: PUT /api.php/v1/users/{id}..
Severity: High (CVSS 8.3/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual PUT /api.php/v1/users/{id}. requests with malformed payloads or SQL meta-characters. Run grep -r 'Plainpad' . 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 'Plainpad' . | 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
Plainpad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 'PUT /api.php/v1/users/{id}.' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
PUT /api.php/v1/users/{id}.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。 -
3Post-deployment verification verify
Replay attack against PUT /api.php/v1/users/{id}. 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。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- report github.com
- web github.com