Vulnerability in open-webui (CVE-2026-44558)
Summary
Vulnerability in open-webui (CVE-2026-44558). Risk of unauthorized operations or information disclosure. Exploitable via POST /api/v1/channels/. Mitigation: upgrade to 0.9.0 or later.
Original description
The description as published by the source.
Channel Access Grants Bypass filter_allowed_access_grants
Affected Component
Channel creation and update endpoints:
backend/open_webui/routers/channels.py(lines 291-340,create_new_channel)backend/open_webui/routers/channels.py(lines 617-638,update_channel_by_id)backend/open_webui/models/channels.py(lines 825-826,set_access_grantscall without filtering)
Affected Versions
Current main branch (commit 6fdd19bf1) and likely all versions supporting user-created group channels with access grants.
Description
All resource routers in Open WebUI (knowledge, models, notes, prompts, tools, skills) call filter_allowed_access_grants() before persisting access grants. This function strips principal_id: "*" wildcard grants from users who lack the relevant sharing.public_* permission, and strips individual user grants from users who lack access_grants.allow_users permission.
The channel router does not call filter_allowed_access_grants on either create or update paths. A non-admin user who can create group channels (or who owns a channel) can submit arbitrary access grants — including public wildcard grants — and those grants are stored verbatim, bypassing the admin's permission framework.
# channels.py — access_grants from form data flow directly into persistence
# No call to filter_allowed_access_grants() anywhere in these paths.
# Compare with knowledge.py / models.py / notes.py / prompts.py / tools.py / skills.py,
# all…
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-2026-44558 has been found in open-webui.
Attackers can target a specific entry point like POST /api/v1/channels/ over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: upgrade open-webui to 0.9.0 or later.
If unsure, ask your IT team or search "open-webui CVE-2026-44558" on the vendor's site.
CVE-2026-44558 (open-webui) — CWE-862 / CVSS v3 5.4
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/v1/channels/ / POST /api/v1/channels/{id}/update / create_new_channel / update_channel_by_id
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-862) exists in open-webui. Attackers reach the vulnerable code path via POST /api/v1/channels/.
Check the vendor advisory for the affected versions of open-webui. Attack surface: POST /api/v1/channels/ / POST /api/v1/channels/{id}/update / create_new_channel / update_channel_by_id.
Severity: Medium (CVSS 5.4/10). Risk of unauthorized operations or information disclosure.
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 POST /api/v1/channels/ 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 'POST /api/v1/channels/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/v1/channels/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 0.9.0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 POST /api/v1/channels/ 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 nvd.nist.gov
- package github.com
- web github.com
- web github.com