Vulnerability in Vaultwarden (CVE-2026-43911)
Summary
Vulnerability in Vaultwarden (CVE-2026-43911). Confidential information can be exposed externally. 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, refresh tokens are not invalidated when the user's security_stamp is rotated by some security-sensitive operations (password change, KDF change, key rotation, email change, org admin password reset, emergency access takeover). This allows an attacker holding a previously obtained refresh token to maintain session access even after the user has taken action to secure their account. 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-2026-43911 has been found in Vaultwarden.
Confidential information can be exposed externally. CVSS score: 6.8/10.
What to do: upgrade Vaultwarden to 1.35.5 or later.
If unsure, ask your IT team or search "Vaultwarden CVE-2026-43911" on the vendor's site.
CVE-2026-43911 (Vaultwarden) — CWE-613 / CVSS v3 6.8
Attack vector: remote (network-reachable) / no user interaction
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.
A vulnerability (CWE-613) exists in Vaultwarden.
Check the vendor advisory for the affected versions of Vaultwarden.
Severity: Medium (CVSS 6.8/10). Confidential information can be exposed externally.
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 request patterns matching this CVE's known IOCs. 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
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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。 -
2Apply 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を含めること。
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3Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- exploit github.com