CVE-2026-45045
Fiber: X-Real-IP Spoofing via Header.Add() in BalancerForward
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-290 |
| Vendor | gofiber |
| Product | fiber |
| Published | Jul 8, 2026 |
| Last Updated | Jul 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Affected Versions
gofiber / fiber
>= 3.0.0-beta.2, < 3.3.0 < 2.52.14
References
github.com: https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876 github.com: https://github.com/gofiber/fiber/pull/4260 github.com: https://github.com/gofiber/fiber/pull/4495 github.com: https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396 github.com: https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d github.com: https://github.com/gofiber/fiber/releases/tag/v2.52.14 github.com: https://github.com/gofiber/fiber/releases/tag/v3.3.0