PatchSiren cyber security CVE debrief
CVE-2026-43984 Tautulli CVE debrief
CVE-2026-43984 is a stored cross-site scripting vulnerability in Tautulli, 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.
- Vendor
- Tautulli
- Product
- Unknown
- CVSS
- HIGH 8.9
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-06-04
- Original CVE updated
- 2026-06-04
- Advisory published
- 2026-06-04
- Advisory updated
- 2026-06-04
Who should care
Administrators of Tautulli instances, especially those with guest access enabled, should be aware of this vulnerability and take immediate action to upgrade to version 2.17.1 or later.
Technical summary
The vulnerability has a CVSS score of 8.9 and is classified as HIGH severity. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L. The weakness is classified as CWE-79.
Defensive priority
HIGH
Recommended defensive actions
- Upgrade Tautulli to version 2.17.1 or later.
- Review and monitor logs for suspicious activity.
- Restrict access to the `logFile` view to only necessary personnel.
Evidence notes
The vulnerability was published on June 4, 2026, and modified on the same day. The CVE record can be found at [cve-org]. The NVD detail can be found at [nvd]. The source item URL is [source-item]. References can be found at [ref-4] and [ref-5].
Official resources
CVE-2026-43984 was published on 2026-06-04T16:16:37.883Z and modified on 2026-06-04T18:16:30.593Z.