IP-based control bypass via appended X-Real-IP
Published Jul 8, 2026 · Updated Jul 8, 2026
Authentication bypass in GoFiber Fiber before 2.52.14 and 3.0.0-beta.2 through 3.2.0 allows remote attackers to spoof client IPs. BalancerForward calls Header.Add for X-Real-IP, preserving an attacker-supplied first value instead of replacing it with the connection address. Reachability requires an application to use BalancerForward and an upstream service to trust the first value for logging, rate limiting, geofencing, or IP access control.
Summary
What happened
Authentication bypass in GoFiber Fiber before 2.52.14 and 3.0.0-beta.2 through 3.2.0 allows remote attackers to spoof client IPs. BalancerForward calls Header.Add for X-Real-IP, preserving an attacker-supplied first value instead of replacing it with the connection address. Reachability requires an application to use BalancerForward and an upstream service to trust the first value for logging, rate limiting, geofencing, or IP access control.
The record
- CVE
- CVE-2026-45045
- Published
- Jul 8, 2026
- Updated
- Jul 8, 2026
- Vendor
- GoFiber
- Product
- Fiber
- Classifications
- CWE-290, T1036
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 8, 2026CVE publishedPublication date reported by the CVE source.
- Jul 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.52.14
- Affected versionversion=>= 3.0.0-beta.2, < 3.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- GHSA X-Real-IP spoofing request reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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