Vulnerability in open-webui (CVE-2026-56398)
Summary
Vulnerability in open-webui (CVE-2026-56398). Confidential information can be exposed externally. Exploitable via GET /api/v1/users/{id}/profile/image. Mitigation: upgrade to 0.9.5 or later.
Original description
The description as published by the source.
Open WebUI before 0.9.5 contains a stored cross-site scripting vulnerability in the OAuth authentication flow where the picture claim URL MIME type is inferred from file extension rather than Content-Type header, allowing SVG files to bypass the profile image validator and be stored as data URIs. Authenticated users who visit the profile image endpoint receive attacker-controlled SVG content with inline disposition and no default security headers, enabling script execution in the same origin to steal authentication tokens and achieve account takeover.
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-2026-56398 has been found in open-webui.
Attackers can target a specific entry point like GET /api/v1/users/{id}/profile/image over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.3/10.
What to do: upgrade open-webui to 0.9.5 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-56398" on the vendor's site.
CVE-2026-56398 (open-webui) — CWE-20 / CVSS v3 7.3
Attack vector: remote (network-reachable)
Attack surface: GET /api/v1/users/{id}/profile/image / picture / mimetypes.guess_type / validate_profile_image_url
Patched: 0.9.5 — 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-20) exists in open-webui. Attackers reach the vulnerable code path via GET /api/v1/users/{id}/profile/image.
Check the vendor advisory for the affected versions of open-webui. Attack surface: GET /api/v1/users/{id}/profile/image / picture / mimetypes.guess_type / validate_profile_image_url.
Severity: High (CVSS 7.3/10). Confidential information can be exposed externally.
Update to 0.9.5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /api/v1/users/{id}/profile/image requests with malformed payloads or SQL meta-characters. 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。 -
2Hunt for indicators of compromise detect
grep 'GET /api/v1/users/{id}/profile/image' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /api/v1/users/{id}/profile/image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。 -
3Apply patch patch
Upgrade open-webui to 0.9.5ステージング環境で 0.9.5 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /api/v1/users/{id}/profile/image 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。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory vulncheck.com
- advisory github.com
- package github.com
- web github.com
- web github.com