Vulnerability · Published Aug 14, 2026 · Assigned by VulnCheck
CVE-2026-72815go-chi chi v5.2.1 IP Spoofing via X-Forwarded-For Header
Medium 6.9
In plain English
A medium-severity authentication bypass by spoofing in chi from go-chi. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official description
go-chi chi versions >= 5.2.1 and before 5.3.0 contain an IP spoofing vulnerability in the RealIP middleware, which blindly trusts the first (leftmost) value of the X-Forwarded-For HTTP header. A remote attacker can bypass IP-based access control lists and rate-limiting mechanisms, and forge log entries, by supplying a spoofed IP address in the X-Forwarded-For header. The issue is fixed in version 5.3.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | golang-github-go-chi-chi | no fix listed | DEBIAN-CVE-2026-72815 |
| Debian:13 | golang-github-go-chi-chi | no fix listed | DEBIAN-CVE-2026-72815 |
| Debian:14 | golang-github-go-chi-chi | 5.3.0-1 | DEBIAN-CVE-2026-72815 |
| Go | github.com/go-chi/chi/v5 | 5.3.0 | GHSA-3fxj-6jh8-hvhx |
| Go | github.com/go-chi/chi/v5 | 5.3.0 | GO-2026-5774 |
| Go | github.com/go-chi/chi/v5/middleware | 5.3.0 | GHSA-3fxj-6jh8-hvhx |
| Ubuntu:22.04:LTS | golang-github-go-chi-chi | no fix listed | UBUNTU-CVE-2026-72815 |
| Ubuntu:24.04:LTS | golang-github-go-chi-chi | no fix listed | UBUNTU-CVE-2026-72815 |
| Ubuntu:26.04:LTS | golang-github-go-chi-chi | no fix listed | UBUNTU-CVE-2026-72815 |
Affected products (as reported)
Weakness: CWE-290 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
References
- GitHub Security Advisory (GHSA-3fxj-6jh8-hvhx) vendor-advisory
- VulnCheck Advisory: go-chi chi v5.2.1 IP Spoofing via X-Forwarded-For Header third-party-advisory