Cyber Resilience

CVE-2025-50578

Open Redirect in Linuxserver Docker-Heimdall 2.6.3-ls307

Public PoCOpen Redirect
Published
30 July 2025
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.028 85th percentile
Risk Priority 78 floored blend · peak EPSS

Summary

CVE-2025-50578 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Linuxserver Docker-Heimdall. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 15% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

LinuxServer.io Heimdall version 2.6.3-ls307 is affected by insufficient validation of user-supplied HTTP headers, specifically X-Forwarded-Host and Referer. The flaw permits Host Header Injection and Open Redirect attacks because the application trusts untrusted input without proper sanitization, as indicated by the associated CWEs for improper input validation, injection, and open redirect.

An unauthenticated remote attacker can supply crafted headers to force the application to load resources from attacker-controlled domains or redirect users to arbitrary locations. This can result in phishing campaigns, UI redress attacks, and potential session theft, consistent with the CVSS 9.8 rating reflecting network-exploitable integrity and confidentiality impacts without authentication or user interaction.

The EPSS score rose from a low baseline to a peak of 0.0575 on 2026-04-02 before receding to the current value of 0.0318, indicating measurable post-disclosure exploitation interest that warrants renewed attention. References point to the upstream GitHub repository and a detailed issue discussion but provide no explicit patch or mitigation guidance in the available details.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1221 Template Injection Stealth
Adversaries may create or modify references in user document templates to conceal malicious code or force authentication attempts.
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
T1674 Input Injection Execution
Adversaries may simulate keystrokes on a victim’s computer by various means to perform any type of action on behalf of the user, such as launching the command interpreter using keyboard shortcuts, typing an inline script to be executed,…
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-5043Shared CWE-20, CWE-74
CVE-2024-11234Shared CWE-20, CWE-74
CVE-2023-4197Shared CWE-20, CWE-74
CVE-2023-38060Shared CWE-20, CWE-74
CVE-2020-13942Shared CWE-20, CWE-74
CVE-2024-45612Shared CWE-20, CWE-74
CVE-2025-69205Shared CWE-20, CWE-74
CVE-2023-0493Shared CWE-74
CVE-2024-48918Shared CWE-20, CWE-74
CVE-2023-23749Shared CWE-74

Affected Assets

linuxserver
docker-heimdall
2.6.3-ls307

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V3.7.2
  • V1.2.1
  • V1.2.3
  • V1.2.5

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing input validation through analysis or test cases.

SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.

Information flow enforcement can restrict redirects to only approved/trusted destinations, stopping untrusted user-supplied URLs from being followed.

Requiring documented development standards and tools can embed input-validation practices into the engineering process.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

A.8.15 Logging partial match
finds

Logging supports detection of injection attempts but does not prevent the weakness.

finds

Monitoring activities can identify active injection attacks after they occur.

mitigates

Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.

prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References