How severe is CVE-2025-50578?

CVE-2025-50578 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-50578 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-50578?

CVE-2025-50578 affects Linuxserver Docker-heimdall. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-50578?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-50578 have an EU (EUVD) identifier?

Yes. CVE-2025-50578 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23174.

When was CVE-2025-50578 published?

CVE-2025-50578 was published on 2025-07-30 and last updated on 2026-06-17.

CVE-2025-50578

CVE-2025-50578 is a critical-severity vulnerability in Linuxserver Docker-heimdall with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-23174
Weakness: CWE-20
Affected product: Linuxserver Docker-heimdall
Published: 2025-07-30
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2025-50578?: CVE-2025-50578 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-50578 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-50578?: CVE-2025-50578 affects Linuxserver Docker-heimdall. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-50578?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-50578 have an EU (EUVD) identifier?: Yes. CVE-2025-50578 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-23174.
When was CVE-2025-50578 published?: CVE-2025-50578 was published on 2025-07-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:linuxserver:docker-heimdall:2.6.3-ls307:*:*:*:*:*:*:*

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