CVE-2026-72815 go-chi chi v5.2.1 IP Spoofing via X-Forwarded-For Header
Attackers can bypass IP-based access controls and rate limits by spoofing the X-Forwarded-For header in go-chi chi middleware.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72815?
CVE-2026-72815 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 >= 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.
Weakness: CWE-290
Which versions are affected by CVE-2026-72815?
3 open source packages ship an affected version, including github.com/go-chi/chi/v5/middleware and github.com/go-chi/chi/v5.
| Package | Affected | Fixed in |
|---|---|---|
github.com/go-chi/chi/v5/middleware Go | From 5.2.1 | 5.3.0 |
github.com/go-chi/chi/v5/middleware Go | From 5.2.1 | 5.3.0 |
github.com/go-chi/chi/v5 Go | From 5.2.1 | 5.3.0 |
Linux distribution packages (1)
cloudflared openSUSE:Tumbleweed | All versions | 2026.8.2-1.1 |
How do I fix CVE-2026-72815?
Upgrade github.com/go-chi/chi/v5/middleware to 5.3.0 or later.
Is CVE-2026-72815 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72815 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as CLEANSTART-2026-CG94137, CLEANSTART-2026-SZ57384, CLEANSTART-2026-YO03060, DEBIAN-CVE-2026-72815, GHSA-3fxj-6jh8-hvhx, GHSA-qgxv-hqxp-4rcx and 92 more.