CVE-2026-45045

Summary

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.

Affected Software

VendorProductVersion RangeStatus
gofiberfiber>= 3.0.0-beta.2, < 3.3.0affected
gofiberfiber< 2.52.14affected

Weaknesses

  • CWE-290: CWE-290: Authentication Bypass by Spoofing

References