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CVE-2026-45045
Fiber: X-Real-IP Spoofing via Header.Add() in BalancerForward
Medium5.3EPSS 0.46%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.46% · top 60% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/gofiber/fiber/v2GHSA-gcfq-8gqf-4876 (opens in a new tab)
- Gogithub.com/gofiber/fiber/v3GHSA-gcfq-8gqf-4876 (opens in a new tab)
References (7)
- https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/gofiber/fiber/pull/4260 (opens in a new tab)x_refsource_MISC
- https://github.com/gofiber/fiber/pull/4495 (opens in a new tab)x_refsource_MISC
- https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396 (opens in a new tab)x_refsource_MISC
- https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d (opens in a new tab)x_refsource_MISC
- https://github.com/gofiber/fiber/releases/tag/v2.52.14 (opens in a new tab)x_refsource_MISC
- https://github.com/gofiber/fiber/releases/tag/v3.3.0 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-gcfq-8gqf-4876 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-45045)Record last updated .