CVE-2026-45045
Fiber: X-Real-IP Spoofing via Header.Add() in BalancerForward
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.
INFO
Published Date :
July 8, 2026, 8:16 p.m.
Last Modified :
July 15, 2026, 8:50 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Fiber to version 3.3.0.
- Update Fiber to version 2.52.14.
- Use Header.Set() instead of Header.Add() for X-Real-IP.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45045.
| URL | Resource |
|---|---|
| https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396 | Patch |
| https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d | Patch |
| https://github.com/gofiber/fiber/pull/4260 | Issue Tracking Patch |
| https://github.com/gofiber/fiber/pull/4495 | Issue Tracking Patch |
| https://github.com/gofiber/fiber/releases/tag/v2.52.14 | Release Notes |
| https://github.com/gofiber/fiber/releases/tag/v3.3.0 | Release Notes |
| https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45045 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45045
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45045 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45045 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 15, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:* versions up to (excluding) 2.52.14 *cpe:2.3:a:gofiber:fiber:*:*:*:*:*:go:*:* versions from (including) 3.0.0 up to (excluding) 3.3.0 Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d Types: Patch Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/pull/4260 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/pull/4495 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/releases/tag/v2.52.14 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/releases/tag/v3.3.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 09, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-45045', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-09T13:19:42.395861Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'gofiber', 'product': 'fiber', 'versions': [{'status': 'affected', 'version': '>= 3.0.0-beta.2, < 3.3.0'}, {'status': 'affected', 'version': '< 2.52.14'}]}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-290 Added Reference https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396 Added Reference https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d Added Reference https://github.com/gofiber/fiber/pull/4260 Added Reference https://github.com/gofiber/fiber/pull/4495 Added Reference https://github.com/gofiber/fiber/releases/tag/v2.52.14 Added Reference https://github.com/gofiber/fiber/releases/tag/v3.3.0 Added Reference https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876