high CVSS 7.5 EPSS <0.1%

CVE-2026-31831·Python vulnerability

Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the /newsletter/image/images API endpoint is vulnerable to path traversal, allowing unauthenticated attackers to read arbitrary files from the application server's filesystem. This issue has been patched in version 2.17.0.

Severity
high
Software
Python
Fixed in
2.17.0
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 23% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2026-31831 scores 7.5 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

Until: 2.17.0

Fixed in: 2.17.0

How to fix this CVE

Upgrade Tautulli to version 2.17.0 or later to patch the path traversal vulnerability in the newsletter image API endpoint. This flaw allows unauthorized access to arbitrary files on the server filesystem without authentication. Immediately apply this update to any Tautulli instance exposed to untrusted networks.

sudo dnf upgrade python3

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

GET|POST /newsletter/image/images.*\.\.[\/\\]

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Block HTTP requests to /newsletter/image/images endpoints containing path traversal sequences (../ or ..\ patterns). Implement strict input validation to reject any image path parameters containing directory traversal characters. Require authentication for all newsletter API endpoints.

How to check if you are affected

  1. Run `tautulli --version` or check the version in Tautulli's web interface under Settings > General to identify the installed version
  2. If running Tautulli pre-2.17.0, verify the /newsletter/image/images endpoint is accessible by checking the service logs: `grep -i 'newsletter' /var/log/tautulli/tautulli.log`
  3. Search application logs for suspicious path traversal patterns: `grep -E '\.\./' /var/log/tautulli/tautulli.log | grep newsletter`
  4. After upgrading, confirm the new version with `tautulli --version` and restart the service: `sudo systemctl restart tautulli`

FAQ

What is CVE-2026-31831?

CVE-2026-31831 is a path traversal vulnerability in Tautulli's newsletter image API endpoint that allows unauthenticated attackers to read arbitrary files from the server's filesystem by manipulating file path parameters.

Is CVE-2026-31831 being actively exploited?

No, this vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities catalog and no public exploits are available, though the flaw is easily discoverable and should be patched immediately.

What versions of Tautulli are affected by CVE-2026-31831?

All Tautulli versions prior to 2.17.0 are vulnerable. The issue was patched in version 2.17.0 and later.

How do I check if my Tautulli instance is vulnerable to CVE-2026-31831?

Navigate to Tautulli's Settings menu and check the version number under General settings. If the version is below 2.17.0, your instance is vulnerable.

Does Defensia detect CVE-2026-31831?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Tautulli is installed on a monitored server, CVE-2026-31831 will appear in your dashboard with remediation steps.

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References

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