What’s Vulnerable › Vulnerabilities

CVE-2026-72817: go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-14 · updated 2026-10-08
• Weakness: CWE-345

Description

go-chi/chi versions 0.9.0 before 5.3.0 contains an IP spoofing vulnerability in the RealIP middleware, which resolves the request source IP (Request.RemoteAddr) using the first IP in the X-Forwarded-For header without validating trusted proxies. A malicious client can prepend a forged IP as the first value of the X-Forwarded-For header to spoof the request source IP, potentially bypassing access controls or falsifying request logs.

Affected products

• go-chi chi: from 0.9.0 before 5.3.0 — fixed in 5.3.0

How to fix

Upgrade to a fixed version: go-chi chi 5.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/go-chi/chi/security/advisories/GHSA-9g5q-2w5x-hmxf
• https://www.vulncheck.com/advisories/go-chi-chi-before-ip-spoofing-via-x-forwarded-for

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