CVE-2026-43986

Description

Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Versions prior to 2.17.1 expose a public `/image/<hash>` route that resolves attacker-controlled entries from `image_hash_lookup` and replays them through the same server-side image fetch logic used by authenticated image proxying. A low-privilege guest user can seed a malicious external image URL into this lookup table and then trigger server-side fetches through a fully unauthenticated endpoint. This turns an authenticated SSRF primitive into a persistent unauthenticated SSRF gadget. Once the malicious hash entry exists, any external user can request `/image/<hash>.png` and cause the PMS or Tautulli host to fetch an arbitrary attacker-chosen URL. Version 2.17.1 patches the issue.

CVSS v3.1 Score

9.9

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-918 Server-Side Request Forgery (SSRF)

References

Other References

https://github.com/Tautulli/Tautulli/releases/tag/v2.17.1 https://github.com/Tautulli/Tautulli/security/advisories/GHSA-m6j6-rc2c-8vpm https://github.com/Tautulli/Tautulli/security/advisories/GHSA-m6j6-rc2c-8vpm

Frequently Asked Questions

What is CVE-2026-43986? +

Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Versions prior to 2.17.1 expose a public `/image/<hash>` route that resolves attacker-controlled entries from `image_hash_lookup` and replays them through the same server-side image fetch logic used by authenticated image proxying. A low-privilege guest user can seed a malicious external image URL into this lookup table and then trigger server-side fetches through a fully unauthenticated endpoint. This turns an authenticated SSRF primitive into a persistent unauthenticated SSRF gadget. Once the malicious hash entry exists, any external user can request `/image/<hash>.png` and cause the PMS or Tautulli host to fetch an arbitrary attacker-chosen URL. Version 2.17.1 patches the issue. It has a CVSS v3.1 base score of 9.9 (CRITICAL).

How severe is CVE-2026-43986? +

CVE-2026-43986 has a CVSS v3.1 score of 9.9 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-43986? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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