CVE-2026-45045

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.

PUBLISHED Reserved 2026-05-08 | Published 2026-07-08 | Updated 2026-07-09 | Assigner GitHub_M

Problem types

CWE-290: Authentication Bypass by Spoofing

Product status

References

github.com/.../fiber/security/advisories/GHSA-gcfq-8gqf-4876

github.com/gofiber/fiber/pull/4260

github.com/gofiber/fiber/pull/4495

github.com/...ommit/1403cc8292da3220e9316960b4030cc722a0f396

github.com/...ommit/33c9501288ab47a429c8b5e701493f0c3c0af37d

github.com/gofiber/fiber/releases/tag/v2.52.14

github.com/gofiber/fiber/releases/tag/v3.3.0

cve.org (CVE-2026-45045)

nvd.nist.gov (CVE-2026-45045)

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