Bug 2517964

Summary:	CVE-2026-72816 prometheus: go-chi/chi: IP Spoofing via RealIP Middleware allows bypassing access controls [epel-all]
Product:	[Fedora] Fedora EPEL	Reporter:	Joel Chamberlain <jochambe>
Component:	prometheus	Assignee:	Mikel Olasagasti Uranga <mikel>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	epel10	CC:	go-sig, mikel
Target Milestone:	---	Keywords:	Security, SecurityTracking
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:	{"flaws": ["5fca9e5b-6b38-4e4b-9b95-a3e49b4c5b98"]}
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	2515985

Description Joel Chamberlain 2026-08-18 15:53:16 UTC

Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.