Vulnerability in Nextcloud Twofactor WebAuthn (CVE-2025-66558)
Summary
Vulnerability in Nextcloud Twofactor WebAuthn (CVE-2025-66558). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.4.2 or later.
Original description
The description as published by the source.
Nextcloud Twofactor WebAuthn is the WebAuthn Two-Factor Provider for Nextcloud. Prior to 1.4.2 and 2.4.1, a missing ownership check allowed an attack to take-away a 2FA webauthn device when correctly guessing a 80-128 character long random string of letters, numbers and symbols. The victim would then be prompted to register a new device on the next login. The attacker can not authenticate as the victim. This vulnerability is fixed in 1.4.2 and 2.4.1.
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-2025-66558 has been found in Nextcloud Twofactor WebAuthn.
Risk of unauthorized operations or information disclosure. CVSS score: 3.1/10.
What to do: upgrade Nextcloud Twofactor WebAuthn to 1.4.2 or later.
If unsure, ask your IT team or search "Nextcloud Twofactor WebAuthn CVE-2025-66558" on the vendor's site.
CVE-2025-66558 (Nextcloud Twofactor WebAuthn) — CWE-639 / CVSS v3 3.1
Attack vector: remote (network-reachable) / no user interaction
Patched: 1.4.2 — 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-639) exists in Nextcloud Twofactor WebAuthn.
Check the vendor advisory for the affected versions of Nextcloud Twofactor WebAuthn.
Severity: Low (CVSS 3.1/10). Risk of unauthorized operations or information disclosure.
Update to 1.4.2.
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. Audit SBOM/dependencies 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
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Nextcloud Twofactor WebAuthn を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade Nextcloud Twofactor WebAuthn to 1.4.2ステージング環境で 1.4.2 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。