## Echo: Reverse Proxy Forwards Attacker-Supplied X-Real-IP to Upstream by Default

- 種別: advisory
- 重大度: medium
- 関連技術: go, github
- CVE: CVE-2026-118651
- 公開日時: 2026-10-28T19:53:24.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-99jh-6h7p-pp36)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-99jh-6h7p-pp36

影響: go:github.com/labstack/echo/v5 < 5.4.0 → 5.4.0, go:github.com/labstack/echo/v4 >= 4.0.0, <= 4.16.2
The Echo proxy middleware (middleware/proxy.go) preserves an incoming X-Real-IP header verbatim and forwards it to the upstream service when Echo#IPExtractor is not configured — which is the default. Because any HTTP client can supply an arbitrary X-Real-IP value, an attacker can cause Echo to relay a spoofed client IP address to every upstream service behind the proxy, undermining upstream IP-based access controls, rate limiting, audit logging, and geo-restriction. Affected Component - middlew…