Coder up to 2.34.6 ExtractRealIPAddress X-Forwarded-For input validation

Summaryinfo

A vulnerability marked as problematic has been reported in Coder up to 2.34.6. Impacted is the function ExtractRealIPAddress. Performing a manipulation of the argument X-Forwarded-For results in input validation. This vulnerability is known as CVE-2026-111934. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Coder up to 2.34.6. This affects the function ExtractRealIPAddress. The manipulation of the argument X-Forwarded-For with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on integrity. The summary by CVE is:

Coder before 2.34.7 contains an IP spoofing vulnerability in the ExtractRealIPAddress middleware that trusts the leftmost, client-supplied X-Forwarded-For value instead of the client IP appended by a reverse proxy. Attackers can send forged X-Forwarded-For values through appending proxies to bypass per-IP rate limits on login, one-time passcode, and password validation endpoints, enabling brute-force attacks, and to falsify IP addresses recorded in audit logs.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-111934 since 10/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.34.7 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-103301). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Coder

Version

• 2.34.0
• 2.34.1
• 2.34.2
• 2.34.3
• 2.34.4
• 2.34.5
• 2.34.6

Website

• Product: https://github.com/coder/coder/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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