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CVE-2026-42849
critical
CVSS 9.3
Cross-Site Scripting (XSS) in authentik (CVE-2026-42849)
Summary
cross-site scripting in authentik (CVE-2026-42849). Confidential information can be exposed externally. Mitigation: upgrade to `2025.12.5, 2026.2.3` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-42849** has been found in authentik.
Confidential information can be exposed externally. CVSS score: 9.3/10.
What to do: upgrade authentik to **2025.12.5, 2026.2.3** or later.
If unsure, ask your IT team or search "authentik CVE-2026-42849" on the vendor's site.
CVE-2026-42849 (authentik) — CWE-79 / CVSS v3 9.3
Attack vector: remote (network-reachable) / unauthenticated
Patched: `2025.12.5, 2026.2.3` — 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.
❓ What is the problem
**Cross-site scripting (XSS)** (CWE-79) exists in authentik.
📍 Affected scope
authentik — .
🔥 Severity
Severity: Critical (CVSS 9.3/10). Confidential information can be exposed externally
🔧 How to fix
Update to **2025.12.5, 2026.2.3**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'authentik' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'authentik' . | 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 `authentik` を grep し、稼働しているサービス・バージョンを把握する。
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6Apply patch patch
Upgrade authentik to 2025.12.5, 2026.2.3ステージング環境で 2025.12.5, 2026.2.3 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 3 で見つけた異常検知の続報チェックを含めること。
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7Post-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 Step 3 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
Bitnami
authentik
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2025.12.5"},{"introduced":"2026.0.0"},{"fixed":"2026.2.3"}]}]