CVE-2026-72815
Description
A flaw was found in the go-chi chi RealIP middleware. This vulnerability allows a remote attacker to spoof their IP address by manipulating the X-Forwarded-For HTTP header. By exploiting this, an attacker can bypass IP-based access control lists and rate-limiting mechanisms, and forge log entries, potentially leading to unauthorized access or misattribution of actions.
Statement
An IP spoofing flaw exists in go-chi/chi's RealIP middleware. When parsing incoming HTTP requests, the middleware blindly trusts the leftmost IP address in the X-Forwarded-For header without verifying proxy chain trust. Remote unauthenticated attackers can supply arbitrary client IP addresses to bypass IP-based access control lists (ACLs), evade rate-limiting rules, or forge audit trail logs, posing a Low impact to confidentiality and integrity.
Mitigation
Do not rely on the `RealIP` middleware when accepting connections from untrusted networks. Instead, configure an upstream reverse proxy (such as NGINX or HAProxy) to overwrite or sanitize client-supplied `X-Forwarded-For` headers before forwarding traffic to the application.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | Low | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context; Bypass Protection Mechanism
An attacker can access any functionality that is inadvertently accessible to the source.
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