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TI-2026-42363 Aliases CVE-2026-59220GHSA-ffpj-xv5c-p3gw

Open WebUI: ReDoS in skill-mention regexes causes whole-instance DoS on default config

Priority MEDIUM 62CWE-1333Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-1333.

Summary

Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.2 before 0.10.0, the SKILL_MENTION_RE and strip_re regular expressions in backend/open_webui/utils/middleware.py parsed <$skillId|label> skill mentions with overlapping quantifiers, allowing an authenticated chat message containing <$ without a closing > to trigger quadratic backtracking and block the asyncio event loop. This issue is fixed in version 0.10.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00573 47th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed open-webui (open-webui): 0.10.0open-webui (PyPI): 0.10.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
open-webuiopen-webui0.9.2 to before 0.10.00.10.0Patch availableCNA
—open-webui (PyPI)0.9.2 to before 0.10.00.10.0Patch availableGHSA-ffpj-xv5c-p3gw
  • open-webui Vendoropen-webui Affected 0.9.2 to before 0.10.0 Fixed in 0.10.0 Patch available CNA
  • open-webui (PyPI) Vendor— Affected 0.9.2 to before 0.10.0 Fixed in 0.10.0 Patch available GHSA-ffpj-xv5c-p3gw

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:*0.9.2 to before 0.10.0Vulnerableopen-webui
  • cpe:2.3:a:openwebui:open_webui:*:*:*:*:*:*:*:* Versions 0.9.2 to before 0.10.0 Vulnerable ·open-webui

Remediation

  • Fix · CNA open-webui (open-webui) Fixed in 0.10.0
  • Fix · GHSA-ffpj-xv5c-p3gw open-webui (PyPI) Fixed in 0.10.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59220
  2. 2026-10-03 Alias added: GHSA-ffpj-xv5c-p3gw

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • TI-2024-06216 Open WebUI Arbitrary File Upload + Path Traversal CVSS 3.1HIGH 8.8
  • TI-2024-07467 Improper Authentication in open-webui/open-webui CVSS 3.1HIGH 8.2
  • TI-2026-42359 Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id CVSS 3.1CRITICAL 9.0
  • TI-2026-40759 open-webui - Remote Code Execution via CORS Misconfiguration and Session Validation CVSS 4.0CRITICAL 9.0
  • TI-2024-07431 Cross-site Scripting (XSS) in open-webui/open-webui CVSS 3.0CRITICAL 9.0
  • TI-2026-60021 Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin CVSS 3.1HIGH 8.7
See all 154 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences