CVE-2026-45045
MEDIUMFiber: X-Real-IP Spoofing via Header.Add() in BalancerForward
Title source: cnaDescription
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 (7)
Core 7
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/pull/4260
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/pull/4495
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/releases/tag/v2.52.14
X_Refsource_Misc x_refsource_misc
https://github.com/gofiber/fiber/releases/tag/v3.3.0
Scores
CVSS v3
5.3
EPSS
0.0046
EPSS Percentile
37.5%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-290
Status
published
Products (2)
gofiber/fiber
< 2.52.14 (2 CPE variants)
gofiber/fiber
>= 3.0.0-beta.2, < 3.3.0
Published
Jul 08, 2026
Tracked Since
Jul 09, 2026