CVE-2026-72816: Authentication Bypass by Spoofing in go-chi chi
go-chi/chi through 5.2.1 contains an IP spoofing vulnerability in the RealIP middleware (middleware/realip.go). The realIP() function reads client-controlled headers (True-Client-IP, X-Real-IP, and X-Forwarded-For) and overwrites r.RemoteAddr without verifying that the request originated from a trusted proxy. Attackers can supply arbitrary IP addresses in these headers to bypass IP-based access controls, evade rate limiting and geo-IP restrictions, and pollute audit logs. Fixed in 5.3.0.
AI Analysis
Technical Summary
The go-chi/chi web framework through version 5.2.1 contains an IP spoofing vulnerability in its RealIP middleware (middleware/realip.go). The realIP() function accepts client-controlled headers such as True-Client-IP, X-Real-IP, and X-Forwarded-For and overwrites the request's RemoteAddr field without verifying that the request originated from a trusted proxy. This flaw enables attackers to supply arbitrary IP addresses in these headers, potentially bypassing IP-based access controls, evading rate limiting and geo-IP restrictions, and polluting audit logs. The vulnerability is addressed in version 5.3.0.
Potential Impact
Attackers can spoof IP addresses by manipulating client-controlled headers, allowing them to bypass IP-based access controls, evade rate limiting and geo-IP restrictions, and corrupt audit logs. This can undermine security policies relying on accurate client IP information.
Mitigation Recommendations
Upgrade to go-chi/chi version 5.3.0 or later, where this vulnerability is fixed. Until then, avoid relying solely on the RealIP middleware for IP-based security controls or implement additional verification of trusted proxies. Patch status is confirmed fixed in 5.3.0.
CVE-2026-72816: Authentication Bypass by Spoofing in go-chi chi
Description
go-chi/chi through 5.2.1 contains an IP spoofing vulnerability in the RealIP middleware (middleware/realip.go). The realIP() function reads client-controlled headers (True-Client-IP, X-Real-IP, and X-Forwarded-For) and overwrites r.RemoteAddr without verifying that the request originated from a trusted proxy. Attackers can supply arbitrary IP addresses in these headers to bypass IP-based access controls, evade rate limiting and geo-IP restrictions, and pollute audit logs. Fixed in 5.3.0.
CVSS v4.0
Score 6.9medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The go-chi/chi web framework through version 5.2.1 contains an IP spoofing vulnerability in its RealIP middleware (middleware/realip.go). The realIP() function accepts client-controlled headers such as True-Client-IP, X-Real-IP, and X-Forwarded-For and overwrites the request's RemoteAddr field without verifying that the request originated from a trusted proxy. This flaw enables attackers to supply arbitrary IP addresses in these headers, potentially bypassing IP-based access controls, evading rate limiting and geo-IP restrictions, and polluting audit logs. The vulnerability is addressed in version 5.3.0.
Potential Impact
Attackers can spoof IP addresses by manipulating client-controlled headers, allowing them to bypass IP-based access controls, evade rate limiting and geo-IP restrictions, and corrupt audit logs. This can undermine security policies relying on accurate client IP information.
Mitigation Recommendations
Upgrade to go-chi/chi version 5.3.0 or later, where this vulnerability is fixed. Until then, avoid relying solely on the RealIP middleware for IP-based security controls or implement additional verification of trusted proxies. Patch status is confirmed fixed in 5.3.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-10T15:12:16.754Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7f0282bf8831d539fec768
Added to database: 08/14/2026, 11:56:50 UTC
Last enriched: 08/14/2026, 12:13:26 UTC
Last updated: 08/14/2026, 13:11:01 UTC
Views: 2
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