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High

Open WebUI Vulnerable to a Session Fixation Attack

  • Disclosed: 20.03.2025
  • Updated: 11.10.2026 13:18

A vulnerability in open-webui/open-webui version 0.3.8 allows an attacker with a user-level account to perform a session fixation attack. The session cookie for all users is set with the default SameSite=Lax and does not have the Secure flag enabled, allowing the session cookie to be sent over HTTP to a cross-origin domain. An attacker can exploit this by embedding a malicious markdown image in a chat, which, when viewed by an administrator, sends the admin's session cookie to the attacker's server. This can lead to a stealthy administrator account takeover, potentially resulting in remote code execution (RCE) due to the elevated privileges of administrator accounts.

Affected software

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PlatformPackageVulnerable versionsFixed in
Python (PyPI) open-webui <= 0.3.8 no fix

References

CVSS score 7.6/10
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
Weakness (CWE)
CWE-79
Platform
Python (PyPI)
Package
open-webui
Disclosed
20.03.2025
Updated
11.10.2026 13:18

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-1720 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-43g4-487m-5q6m - CC BY 4.0

Vulnerability history: open-webui

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (161) in the archive
Total entries
161
First → latest
08.2024 09.2026
Without a fix
11
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 77
  • Medium 75
  • Low 8

Disclosures per year

Severity:
  1. Open WebUI Vulnerable to a Session Fixation Attack this entry
    High · 7.6 CVE-2024-7053 <= 0.3.8 no fix
  2. Open WebUI: Unauthenticated requests can stall the server via uncached OIDC fetches in back-channel logout
    High · 7.5 CVE-2026-87011 >= 0.9.0, < 0.11.1 0.11.1
  3. Open WebUI: Sign-in as another user via wildcard characters in the OAuth subject claim on SQLite
    High · 8.1 CVE-2026-87016 >= 0.6.41, < 0.11.1 0.11.1
  4. Open WebUI: Same-origin XSS to account takeover via terminal port-preview iframe hardcoding allow-same-origin
    High · 8.7 CVE-2026-87995 >= 0.8.11, < 0.11.1 0.11.1
  5. Open WebUI: SSRF into internal services via DNS rebinding in the Playwright web loader
    High · 7.7 CVE-2026-87996 >= 0.9.6, < 0.11.1 0.11.1
  6. Open WebUI: Non-admin users can delete admin-owned external knowledge connections via knowledge base deletion
    High · 7.1 CVE-2026-87998 >= 0.10.0, < 0.11.1 0.11.1
  7. Open WebUI: Any authenticated user can reach the Azure platform channel via server-side web fetch
    High · 7.1 CVE-2026-87999 < 0.11.1 0.11.1
  8. Open WebUI: A folder write-collaborator can permanently delete the owner's chats by deleting a shared subfolder
    High · 8.1 CVE-2026-70494 >= 0.10.0, < 0.11.0 0.11.0
  9. Open WebUI: Stored XSS via unescaped KaTeX render-error fallback in rendered messages
    High · 8.7 CVE-2026-70492 >= 0.10.0, < 0.11.0 0.11.0
  10. Open WebUI: Same-origin XSS to account takeover via terminal file-preview iframe hardcoding allow-same-origin
    High · 8.2 CVE-2026-70486 >= 0.9.0, < 0.11.0 0.11.0
  11. Open WebUI: Any authenticated user can reach internal services and cloud metadata via NAT64-encoded URLs
    High · 7.1 CVE-2026-70485 >= 0.9.0, < 0.11.0 0.11.0
  12. Open WebUI: Account takeover via OAuth token exchange accepting tokens issued to any client
    High · 8.1 CVE-2026-70482 >= 0.8.0, < 0.11.0 0.11.0
  13. Open WebUI: SSRF into internal services via unvalidated sub-resource requests in the Playwright web loader
    High · 7.7 CVE-2026-70479 >= 0.9.6, < 0.11.0 0.11.0
  14. open-webui terminal proxy path traversal guard bypass via 9x encoded traversal
    High · 7.7 CVE-2026-59221 >= 0.9.6, < 0.10.0 0.10.0
  15. Open WebUI: Terminal proxy forwards a spoofable, integrity-unbound user identity to the upstream (X-User-Id header and ws_terminal session_id query injection)
    High · 8.0 CVE-2026-59224 < 0.10.0 0.10.0
  16. Open WebUI: Cross-user code-interpreter and tool execution via unvalidated Socket.IO event-caller session_id
    High · 7.7 CVE-2026-59216 < 0.10.0 0.10.0
  17. Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)
    High · 7.1 CVE-2026-59714 >= 0.9.5, < 0.10.0 0.10.0
  18. Open WebUI: Realtime endpoints accept Redis-revoked JWTs after signout/backchannel logout
    High · 7.1 CVE-2026-59219 >= 0.9.0, < 0.10.0 0.10.0
  19. Open WebUI: Stored web worker XSS via Pyodide
    High · 7.3 CVE-2026-59214 < 0.10.0 0.10.0
  20. Open WebUI vulnerable to Stored XSS via iFrame embeds in response messages
    High · 7.3 CVE-2026-26193 < 0.6.44 0.6.44
  21. Open WebUI vulnerable to Stored XSS via iFrame in citations model
    High · 7.3 CVE-2026-26192 < 0.7.0 0.7.0
Show more (20) Showing 21 of 78

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