CVE-2026-45045
Medium
Description
Fiber is an Express inspired web framework written in Go. Prior to 3.3.0 and 2.52.14, the BalancerForward proxy helper in middleware/proxy/proxy.go uses Header.Add() instead of Header.Set() when injecting X-Real-IP, allowing an attacker-supplied first X-Real-IP value to be forwarded to upstream servers for logging, rate limiting, and access control. This issue is fixed in version 3.3.0 and 2.52.14.
SeverityMedium
CVSS5.3
Exploit probability—
ProductFiber
PublishedJul 8, 2026
First seenJul 8, 2026
Weakness typeCWE-290CWE-290
How to fix
Update
- gofiber fiber2.52.14, 3.3.0 or later
- github.com/gofiber/fiber/v33.3.0 or later
- github.com/gofiber/fiber/v22.52.14 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| gofiber fiber | v < 2.52.14, 3.0.0 ≤ v < 3.3.0 | 2.52.14, 3.3.0 |
| github.com/gofiber/fiber/v3Go | v < 3.3.0 | 3.3.0 |
| github.com/gofiber/fiber/v2Go | v < 2.52.14 | 2.52.14 |
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