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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
2026-07-22
Advisory published
2026-06-04
Advisory updated
2026-07-22

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].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-43984 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-43984

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-43984 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-43984

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.