SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

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`.

CRITICAL 9.8EPSS 2.78%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (2.78%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
2.78% probability · 86th percentile
CISA KEV
Not listed
Weakness
CWE-20, CWE-74, CWE-601
Affected
linuxserver/docker-heimdall
Source
cve@mitre.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.