wizarr: Improper Neutralization of Special Elements Used in a Template Engine
CVE-2026-108264 is a critical-severity improper neutralization of special elements used in a template engine vulnerability in wizarr from Wizarrrr, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected wizarr versions: < 2026.9.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.47% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of wizarr you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
Wizarr is an advanced user invitation and management system for Jellyfin, Plex, Emby, and other media servers. Prior to 2026.9.1, wizard step Markdown supplied through the editor or imported bundles was evaluated by app/blueprints/wizard/routes.py in the application's non-sandboxed Jinja2 environment with application globals exposed. An authenticated user able to create steps, or an administrator importing an untrusted bundle through POST /settings/wizard/import, could execute arbitrary Python when GET /wizard/{server}/{idx} rendered the stored step; app/jinja_filters.py and app/services/wizard_widgets.py contained additional evaluation sinks. This could execute operating-system commands as the application user, disclose the Flask SECRET_KEY, access connected service credentials and the database, and produce stored cross-site scripting. This issue is fixed in 2026.9.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements Used in a Template Engine
The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.
How developers prevent this class of flaw
- Choose a template engine that offers a sandbox or restricted mode, or at least limits the power of any available expressions, function calls, or commands.
- Use the template engine's sandbox or restricted mode, if available.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Improper Neutralization of Special Elements Used in a Template Engine vulnerabilities
- 9.6 Critical severity
- 8.8 High severity
- 9.9 Critical severity
- 7.2 High severity
- 7.2 High severity
- 10.0 Critical severity
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