Authorization Flaw in Open WebUI (CVE-2026-109283)
Summary
Vulnerability in Open WebUI (CVE-2026-109283). Risk of unauthorized operations or information disclosure. Exploitable via POST /api/v1/auths/oauth/{provider}/token/exchange.
Original description
The description as published by the source.
Open WebUI from 0.11.1 before 0.11.4 contains an authorization bypass in the OAuth token exchange endpoint, which reads role claims only from the provider's userinfo response and keeps the user's existing role when no roles claim is found, ignoring roles sent only in the ID token. Users with a linked account whose identity provider role no longer satisfies the OAuth role policy can send a valid provider access token to POST /api/v1/auths/oauth/{provider}/token/exchange to obtain a session retaining their previous role.
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-2026-109283 has been found in Open WebUI.
Attackers can target a specific entry point like POST /api/v1/auths/oauth/{provider}/token/exchange over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Open WebUI CVE-2026-109283" on the vendor's site.
CVE-2026-109283 (Open WebUI) — CWE-863 / CVSS v3 5.4
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/v1/auths/oauth/{provider}/token/exchange
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 Open WebUI. Attackers reach the vulnerable code path via POST /api/v1/auths/oauth/{provider}/token/exchange.
Check the vendor advisory for the affected versions of Open WebUI. Attack surface: POST /api/v1/auths/oauth/{provider}/token/exchange.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
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/v1/auths/oauth/{provider}/token/exchange requests with malformed payloads or SQL meta-characters. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Open WebUI を使っているサービスとバージョンを洗い出す。
-
2Hunt for indicators of compromise detect
grep 'POST /api/v1/auths/oauth/{provider}/token/exchange' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/v1/auths/oauth/{provider}/token/exchange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。 -
3Post-deployment verification verify
Replay attack against POST /api/v1/auths/oauth/{provider}/token/exchange 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
- web github.com
- web nvd.nist.gov
- web disclosure@vulncheck.com
- web github.com