CVE-2026-45045
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.
- CVSS 3.1
- 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-25)
- CWE
- CWE-290
- Published
- Modified
- Record from
- the NVD, synced
Affected
- gofiber:fiber
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-gcfq-8gqf-4876 | Go | github.com/gofiber/fiber/v3 | <3.3.0 | 3.3.0 |
| GHSA-gcfq-8gqf-4876 | Go | github.com/gofiber/fiber/v2 | <2.52.14 | 2.52.14 |
| GO-2026-5887 | Go | github.com/gofiber/fiber/v3 | <3.3.0 | 3.3.0 |