Authorization Flaw in Vaultwarden (CVE-2026-43913)
Summary
Vulnerability in Vaultwarden (CVE-2026-43913). Data can be tampered with by attackers. Exploitable via POST /api/ciphers/purge. Mitigation: upgrade to 1.35.5 or later.
Original description
The description as published by the source.
Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to 1.35.5, Vaultwarden allows an unconfirmed organization owner to purge the entire organization vault. The organization invite flow uses a two-step process: accepting an invite transitions membership from Invited to Accepted, and a separate confirmation by an existing owner upgrades it to Confirmed. The POST /api/ciphers/purge endpoint uses plain Headers and only checks that the membership type is Owner without verifying that the membership status is Confirmed. An authenticated user who has been invited as an organization owner and has accepted the invite and has not yet been confirmed can call this endpoint to hard-delete all ciphers and attachments in the organization,
causing immediate organization-wide data loss. This vulnerability is fixed in 1.35.5.
Source: NIST National Vulnerability Database NVD
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-2026-43913 has been found in Vaultwarden.
Attackers can target a specific entry point like POST /api/ciphers/purge over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 8.1/10.
What to do: upgrade Vaultwarden to 1.35.5 or later.
If unsure, ask your IT team or search "Vaultwarden CVE-2026-43913" on the vendor's site.
CVE-2026-43913 (Vaultwarden) — CWE-863 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/ciphers/purge
Patched: 1.35.5 — 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.
Incorrect authorization (CWE-863) exists in Vaultwarden. Attackers reach the vulnerable code path via POST /api/ciphers/purge.
Check the vendor advisory for the affected versions of Vaultwarden. Attack surface: POST /api/ciphers/purge.
Severity: High (CVSS 8.1/10). Data can be tampered with by attackers.
Update to 1.35.5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /api/ciphers/purge requests with malformed payloads or SQL meta-characters. Run grep -r 'Vaultwarden' . 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 'Vaultwarden' . | 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
Vaultwarden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 'POST /api/ciphers/purge' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/ciphers/purge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 Vaultwarden to 1.35.5ステージング環境で 1.35.5 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 POST /api/ciphers/purge 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
- exploit security-advisories@github.com