CVE-2026-72816
Description
A flaw was found in the go-chi/chi RealIP middleware. This vulnerability allows a remote attacker to perform IP spoofing by supplying arbitrary IP addresses in client-controlled headers. This can lead to bypassing IP-based access controls, evading rate limiting and geo-IP restrictions, and polluting audit logs.
Statement
An IP spoofing flaw exists in go-chi/chi's RealIP middleware (middleware/realip.go). The realIP() function parses untrusted HTTP headers (True-Client-IP, X-Real-IP, X-Forwarded-For) and overwrites r.RemoteAddr without validating upstream proxy identity. Remote unauthenticated attackers can supply arbitrary IP values in these headers to bypass IP-restricted endpoints, subvert rate-limiting controls, or poison application audit logs, posing a Low impact to confidentiality and integrity.
Mitigation
Do not use the `chi/middleware.RealIP` middleware when receiving traffic directly from untrusted networks or unverified proxies. Instead, strip or sanitize client-supplied forwarding headers at an upstream edge proxy or reverse proxy (such as NGINX or HAProxy) before requests reach 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 | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
cve.org: 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
An attacker can access any functionality that is inadvertently accessible to the source.
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