CVE-2026-72816: GO-2026-5777 - Chi's RealIP Middleware allows IP spoofing via unvalidated X-Forwarded-For header in github.com/go-chi/chi

CVE-2026-72816 · Severity: medium · CVSS 6.5 · Published 2026-08-14

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.

Technologies: github.com/go-chi/chi/v5 (Go), github.com/go-chi/chi/v5/middleware (Go). Vendors: Go.

Quick answers

Is CVE-2026-72816 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-72816 being exploited in the wild.
How severe is CVE-2026-72816?
Medium severity, with a CVSS score of 6.5, published 14 August 2026.
Which products and versions are affected?
github.com/go-chi/chi/middleware (Go) SEMVER:introduced=0,last_affected=1.5.5; github.com/go-chi/chi/v2/middleware (Go) SEMVER:introduced=0,last_affected=2.1.1; github.com/go-chi/chi/v3/middleware (Go) SEMVER:introduced=0,last_affected=3.3.5; github.com/go-chi/chi/v4/middleware (Go) SEMVER:introduced=0,last_affected=4.1.3; and 2 more.
Is there a fix for CVE-2026-72816?
Yes. github.com/go-chi/chi/v5 (Go): upgrade to 5.3.0 or later; github.com/go-chi/chi/v5/middleware (Go): upgrade to 5.3.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-72816?
Check whether you run github.com/go-chi/chi/middleware (Go), github.com/go-chi/chi/v2/middleware (Go), github.com/go-chi/chi/v3/middleware (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/go-chi/chi/v5 (Go): upgrade to 5.3.0 or later
    go get github.com/go-chi/chi/v5@v5.3.0
  • github.com/go-chi/chi/v5/middleware (Go): upgrade to 5.3.0 or later
    go get github.com/go-chi/chi/v5/middleware@v5.3.0

Affected products

  • github.com/go-chi/chi/middleware (Go) SEMVER:introduced=0,last_affected=1.5.5
  • github.com/go-chi/chi/v2/middleware (Go) SEMVER:introduced=0,last_affected=2.1.1
  • github.com/go-chi/chi/v3/middleware (Go) SEMVER:introduced=0,last_affected=3.3.5
  • github.com/go-chi/chi/v4/middleware (Go) SEMVER:introduced=0,last_affected=4.1.3
  • github.com/go-chi/chi/v5 (Go) SEMVER:introduced=0,fixed=5.3.0
  • github.com/go-chi/chi/v5/middleware (Go) SEMVER:introduced=0,fixed=5.3.0

Identifiers

  • CVE-2026-72816
  • GHSA-rjr7-jggh-pgcp
  • GO-2026-5777

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