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

  1. 2024: 3
  2. 2025: 21
  3. 2026: 137
Severity:
  1. Open WebUI Vulnerable to a Session Fixation Attack this entry
    High · 7.6 CVE-2024-7053 <= 0.3.8 no fix
  2. High · 7.7 CVE-2026-59221 >= 0.9.6, < 0.10.0 0.10.0
  3. High · 7.3 CVE-2026-59214 < 0.10.0 0.10.0
  4. High · 8.7 CVE-2026-54011 < 0.9.6 0.9.6
  5. High · 7.1 CVE-2026-45349 < 0.9.0 0.9.0
Show more (20) Showing 41 of 78

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