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.

References

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

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

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

https://github.com/gofiber/fiber/pull/4495

https://github.com/gofiber/fiber/pull/4260

https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d

https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396

Details

Source: Mitre, NVD

Published: 2026-07-08

Updated: 2026-07-15

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Severity: Medium

EPSS

EPSS: 0.00455