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CVE-2026-70493— Open WebUI: Any authenticated user can stall a worker via a knowledge-search pattern that backtracks catastrophically

Quick assessment

Affected
open-webui open-webui
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Open WebUI是Open WebUI团队开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.6版本至0.11.0之前版本存在资源管理错误漏洞，该漏洞源于内置知识搜索路径（backend/open_webui/tools/knowledge_fs.py和backend/open_webui/tools/builtin.py）中的正则表达式处理不当，特制模式可能导致CPU核心被占用和事件循环阻塞，造成拒绝服务。

CVSS 6.5 · Medium EPSS 0.59% · P46

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
open-webui open-webui >= 0.9.6, < 0.11.0 affected
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I. Basic Information for CVE-2026-70493

Vulnerability Information
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Vulnerability Title
Open WebUI: Any authenticated user can stall a worker via a knowledge-search pattern that backtracks catastrophically
Source: CVE Program / CVE List V5
Vulnerability Description
Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.6 until 0.11.0, the built-in knowledge search path in backend/open_webui/tools/knowledge_fs.py and backend/open_webui/tools/builtin.py let a chat participant choose a pattern used to grep knowledge files. Patterns containing regex metacharacters were compiled with Python's backtracking re engine and run against every line of every reachable file with no time limit, so a crafted pattern such as (x|x)*y and one matching uploaded file line can pin one CPU core and block the event loop. This causes availability impact for every other user of the affected worker. This issue is fixed in 0.11.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
CWE-1333
Source: CVE Program / CVE List V5
Vulnerability Title
Open WebUI 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Open WebUI是Open WebUI团队开源的一个可扩展、功能丰富、用户友好的自托管 WebUI。 Open WebUI 0.9.6版本至0.11.0之前版本存在资源管理错误漏洞，该漏洞源于内置知识搜索路径（backend/open_webui/tools/knowledge_fs.py和backend/open_webui/tools/builtin.py）中的正则表达式处理不当，特制模式可能导致CPU核心被占用和事件循环阻塞，造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
open-webui open-webui >= 0.9.6, < 0.11.0 -

II. Public POCs for CVE-2026-70493

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III. Intelligence Information for CVE-2026-70493

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Patches & Fixes for CVE-2026-70493 (2)

Vendor Advisories for CVE-2026-70493 (1)

Vendor Pages for CVE-2026-70493 (1)

Same Patch Batch · open-webui · 2026-08-04 · 17 CVEs total

CVE-2026-70492 8.7 HIGH Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
CVE-2026-70486 8.2 HIGH Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcodin
CVE-2026-70482 8.1 HIGH Open WebUI: Account takeover via OAuth token exchange accepting tokens issued to any clien
CVE-2026-70494 8.1 HIGH Open WebUI: A folder write-collaborator can permanently delete the owner's chats by deleti
CVE-2026-70479 7.7 HIGH Open WebUI: SSRF into internal services via unvalidated sub-resource requests in the Playw
CVE-2026-70485 7.1 HIGH Open WebUI: Any authenticated user can reach internal services and cloud metadata via NAT6
CVE-2026-70491 6.5 MEDIUM Open WebUI: Tool source code disclosed to read-only users via the tool list and get endpoi
CVE-2026-70489 6.5 MEDIUM Open WebUI: Instance-wide stall via automation recurrence rules that force multi-second pa
CVE-2026-54020 6.3 MEDIUM Open WebUI: DNS Rebinding SSRF Bypass
CVE-2026-70490 6.3 MEDIUM Open WebUI: Unapproved accounts can open terminal sessions via a WebSocket auth path missi
CVE-2026-70481 5.4 MEDIUM Open WebUI: Any member with write access to a standard channel can edit or delete other me
CVE-2026-70487 5.3 MEDIUM Open WebUI: Cross-user file content disclosure via request-scoped direct model knowledge m
CVE-2026-70484 4.3 MEDIUM Open WebUI: Users denied the image-generation permission can still generate images via cha
CVE-2026-70488 4.3 MEDIUM Open WebUI: Deletion of directories and file embeddings in other knowledge bases via sync
CVE-2026-70480 4.1 MEDIUM Open WebUI: Client-side SSRF via unrestricted external resource loading in Vega/Vega-Lite
CVE-2026-70483 3.1 LOW Open WebUI: Any authenticated user can cancel another user's chat generation via the chat

IV. Related Vulnerabilities

Same product: open-webui
Same vendor: open-webui
Same weakness: CWE-1333

V. Comments for CVE-2026-70493

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