Privilege Escalation in open-webui (CVE-2026-45675)
Summary
Vulnerability in open-webui (CVE-2026-45675). Successful exploitation can lead to full system takeover. Exploitable via signup_handler. Mitigation: upgrade to 0.9.0 or later.
Original description
The description as published by the source.
Open WebUI is a self-hosted artificial intelligence platform designed to operate entirely offline. Prior to 0.9.0, the LDAP and OAuth authentication flows use a TOCTOU (Time-of-Check-Time-of-Use) pattern for first-user admin role assignment. The regular signup handler (signup_handler in auths.py, line 663) was explicitly patched to prevent this race with the comment "Insert with default role first to avoid TOCTOU race", but the LDAP and OAuth code paths were never updated with the same fix. This vulnerability is fixed in 0.9.0.
Source: GitHub Security Advisories (Global) 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-2026-45675 has been found in open-webui.
Attackers can target a specific entry point like signup_handler over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 8.1/10.
What to do: upgrade open-webui to 0.9.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-45675" on the vendor's site.
CVE-2026-45675 (open-webui) — CWE-269 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: signup_handler / admin / DATABASE_ENABLE_SESSION_SHARING / False
Patched: 0.9.0 — 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-269) exists in open-webui. Attackers reach the vulnerable code path via signup_handler without authentication.
Check the vendor advisory for the affected versions of open-webui. Attack surface: signup_handler / admin / DATABASE_ENABLE_SESSION_SHARING / False.
Severity: High (CVSS 8.1/10). Successful exploitation can lead to full system takeover.
Update to 0.9.0.
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 'open-webui' . 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 'open-webui' . | 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
open-webui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 open-webui to 0.9.0ステージング環境で 0.9.0 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。
-
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。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- patch github.com
- web github.com
- web github.com
- web github.com