Open Redirect in Linuxserver Docker-Heimdall

CVE-2025-50578

LinuxServer.io heimdall 2.6.3-ls307 contains a vulnerability in how it handles user-supplied HTTP headers, specifically `X-Forwarded-Host` and `Referer`. An unauthenticated remote attacker can manipulate these headers to perform Host Header Injection and Open Redirect attacks. This allows the loading of external resources from attacker-controlled domains and unintended redirection of users, potentially enabling phishing, UI redress, and session theft. The vulnerability exists due to insufficient validation and trust of untrusted input, affecting the integrity and trustworthiness of the application.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.028 (84.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-50578?
CVE-2025-50578 is a critical-severity vulnerability in Linuxserver Docker-Heimdall, classified under Improper Input Validation. CVSS score: 9.8/10. Published 2025-07-30.
How severe is CVE-2025-50578?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-50578 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.