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CVE-2026-88002 medium CVSS 6.5

Vulnerability in open-webui (CVE-2026-88002)

Summary

Vulnerability in open-webui (CVE-2026-88002). Risk of unauthorized operations or information disclosure. Exploitable via POST /api/v1/chats/new. Mitigation: upgrade to 0.11.1 or later.

Original description

The description as published by the source.

Summary

Chat histories are stored as an unvalidated JSON object. The walk that reconstructs a chat's message chain detected repeats using each message's own id field while moving through the history by map key, so a message that simply omitted id was never recorded as visited. A history whose messages referenced each other in a parent cycle therefore made the walk run forever. Any account with the default user role could store such a chat and trigger the walk, blocking the server for everyone.

Preconditions

One account with the default user role. No administrator rights, no additional permissions, no configuration change and no non-default setting: creating a chat is available to every user out of the box. The attack runs entirely against the attacker's own chat, so no knowledge of any other user's data is needed. Instances where every account is trusted are affected in the sense that the fault is reachable, but require a user acting deliberately.

Impact

The walk is synchronous and runs on the asyncio event loop, so while it spins, every request from every user is blocked, including unauthenticated /health and administrator endpoints. External health checks and orchestrator liveness probes fail alongside the UI. The list it appends to grows without bound, so a memory-capped deployment ends in an out-of-memory kill rather than a hang. The work is not cancelled when the client disconnects, so one fire-and-forget request is enough and the attacker can discon…

Source: NIST National Vulnerability Database 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-2026-88002 has been found in open-webui.
Attackers can target a specific entry point like POST /api/v1/chats/new over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade open-webui to 0.11.1 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-88002" on the vendor's site.

CVE-2026-88002 (open-webui) — CWE-835 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/v1/chats/new / GET /api/v1/chats/stats/usage / GET /health / user
Patched: 0.11.1 — 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

A vulnerability (CWE-835) exists in open-webui. Attackers reach the vulnerable code path via POST /api/v1/chats/new.

📍 Affected scope

Check the vendor advisory for the affected versions of open-webui. Attack surface: POST /api/v1/chats/new / GET /api/v1/chats/stats/usage / GET /health / user.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 0.11.1.

🛡️ 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 POST /api/v1/chats/new 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

  1. 1
    Identify 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。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'POST /api/v1/chats/new' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /api/v1/chats/new 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。

  3. 3
    Apply patch patch 
    Upgrade open-webui to 0.11.1

    ステージング環境で 0.11.1 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。

  4. 4
    Post-deployment verification verify 
    Replay attack against POST /api/v1/chats/new 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

pip open-webui
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.11.1"}]}]

References

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