CVE-2026-72817 go-chi chi 0.9.0 before 5.3.0 IP Spoofing via X-Forwarded-For
Attackers can spoof source IPs via X-Forwarded-For headers in chi middleware, bypassing IP-based access controls and falsifying logs.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72817?
CVE-2026-72817 is a medium-severity vulnerability in go-chi chi, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-345
Which versions are affected by CVE-2026-72817?
11 open source packages ship an affected version, including github.com/go-chi/chi/middleware, github.com/go-chi/chi/v2/middleware and github.com/go-chi/chi/v3/middleware.
| Package | Affected | Fixed in |
|---|---|---|
github.com/go-chi/chi/middleware Go | From 0.9.0 to 1.5.5 | None |
github.com/go-chi/chi/middleware Go | From 0.9.0 to 1.5.5 | None |
github.com/go-chi/chi/v2/middleware Go | All versions to 2.1.1 | None |
github.com/go-chi/chi/v2/middleware Go | All versions to 2.1.1 | None |
github.com/go-chi/chi/v3/middleware Go | All versions to 3.3.5 | None |
github.com/go-chi/chi/v3/middleware Go | All versions to 3.3.5 | None |
5 more packages
github.com/go-chi/chi/v4/middleware Go | All versions to 4.1.3 | None |
github.com/go-chi/chi/v4/middleware Go | All versions to 4.1.3 | None |
github.com/go-chi/chi/v5 Go | All versions | 5.3.0 |
github.com/go-chi/chi/v5/middleware Go | All versions | 5.3.0 |
github.com/go-chi/chi/v5/middleware Go | All versions | 5.3.0 |
Linux distribution packages (2)
trivy openSUSE:Tumbleweed | All versions | 0.74.0-1.1 |
v2ray-core openSUSE:Tumbleweed | All versions | 5.53.0-1.1 |
How do I fix CVE-2026-72817?
Upgrade to a fixed version.
Is CVE-2026-72817 being exploited?
There is no known exploitation of CVE-2026-72817 in the wild and no public exploit code.
Sources
Also known as AZL-96692, CLEANSTART-2026-PL40417, CLEANSTART-2026-UM77147, CLEANSTART-2026-VU46471, DEBIAN-CVE-2026-72817, GHSA-9f4g-6whf-f3pv and 116 more.