CVE-2026-43984 Tautulli has stored XSS in logFile via guest-controlled log_js_errors input
A low-privilege guest can inject JavaScript into logs that executes in an administrator's browser, enabling session hijacking or malicious actions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-43984?
CVE-2026-43984 is a high-severity cross-site scripting vulnerability in Tautulli, published on 4 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Versions prior to 2.17.1 expose `log_js_errors` to any authenticated user, including guest users when guest access is enabled. The endpoint writes attacker-controlled strings directly into the main application log. The administrator-only `logFile` view then reads that log file and embeds it into an HTML response without escaping. This creates a stored cross-site scripting condition where a low-privilege guest can inject HTML or JavaScript into the log file and have it execute in an administrator's browser when the log viewer is opened. Version 2.17.1 patches the issue.
Weakness: CWE-79
Which versions are affected by CVE-2026-43984?
How do I fix CVE-2026-43984?
No fix has been published for CVE-2026-43984 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-43984 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43984 exists.
Sources
Also known as GHSA-f4j7-pjwc-4jrr.