CVE-2026-45045

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
5.3
EG Score
5.3(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
29%
KEV
Not listed

Published

July 2, 2026

Last Modified

July 15, 2026

Advisory Details (7)

Auto-updated Jul 8, 2026
Patch available. Sources: github_release, github, github_commit, github_pr.
github Patch Available

X-Real-IP Spoofing via Header.Add() in BalancerForward · Advisory · gofiber/fiber · GitHub

https://github.com/gofiber/fiber/security/advisories/GHSA-gcfq-8gqf-4876
github_release Patch Available

v3.3.0

Patch available: gofiber/fiber v3.3.0

https://github.com/gofiber/fiber/releases/tag/v3.3.0
github_release Patch Available

v2.52.14

Patch available: gofiber/fiber v2.52.14

https://github.com/gofiber/fiber/releases/tag/v2.52.14
github_pr Patch Available

🐛 fix(proxy): backport BalancerForward X-Real-IP overwrite fix to v2

Patch available: gofiber/fiber v2.52.14 (PR #4495 merged 2026-07-03)

https://github.com/gofiber/fiber/pull/4495
github_pr Patch Available

🐛 fix(proxy): Ensure BalancerForward overwrites X-Real-IP header

Patch available: gofiber/fiber v3.3.0 (PR #4260 merged 2026-05-08)

https://github.com/gofiber/fiber/pull/4260
github_commit Patch Available

commit 33c9501288ab (gofiber/fiber)

Patch available: gofiber/fiber v2.52.14 (contains commit 33c9501288ab)

https://github.com/gofiber/fiber/commit/33c9501288ab47a429c8b5e701493f0c3c0af37d
github_commit Patch Available

commit 1403cc8292da (gofiber/fiber)

Patch available: gofiber/fiber v3.3.0 (contains commit 1403cc8292da)

https://github.com/gofiber/fiber/commit/1403cc8292da3220e9316960b4030cc722a0f396

Vendor Advisories for CVE-2026-45045(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/gofiber/fiber/v2———
github.com/gofiber/fiber/v3—3.3.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 12:26 UTCEG score recompute
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-26 14:54 UTCEPSS rescore
  4. 2026-07-26 13:06 UTCEG score recompute
  5. 2026-07-25 14:18 UTCEPSS rescore
  6. 2026-07-24 14:17 UTCEPSS rescore
  7. 2026-07-23 14:18 UTCEPSS rescore
  8. 2026-07-23 03:16 UTCEG score recompute
  9. 2026-07-22 14:08 UTCEPSS rescore
  10. 2026-07-21 15:24 UTCEPSS rescore
  11. 2026-07-20 17:08 UTCEPSS rescore
  12. 2026-07-19 14:31 UTCEPSS rescore
  13. 2026-07-19 02:29 UTCEPSS rescore
  14. 2026-07-18 10:04 UTCEPSS rescore
  15. 2026-07-16 17:03 UTCEPSS rescore
  16. 2026-07-15 16:57 UTCEPSS rescore
  17. 2026-07-15 02:00 UTCEPSS rescore
  18. 2026-07-13 22:30 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-02 14:01 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45045?
CVE-2026-45045 is a medium vulnerability published on July 2, 2026. 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…
When was CVE-2026-45045 disclosed?
CVE-2026-45045 was first published in the National Vulnerability Database on July 2, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45045 actively exploited?
CVE-2026-45045 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 71.1% of all scored CVEs.
What is the CVSS score of CVE-2026-45045?
CVE-2026-45045 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-45045?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45045, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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