Echo has Rate Limiter Bypass via Spoofed X-Forwarded-For Header in Default Configuration

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

Echo is a Go web framework. From 4.0.0 until 5.1.0, Context.RealIP falls back to client-supplied X-Forwarded-For or X-Real-IP values when Echo.IPExtractor is unset, and the default RateLimiter uses that result as its client identifier. A remote attacker can rotate arbitrary forwarded-address values to obtain new rate-limit buckets and bypass IP-based throttling used for controls such as brute-force or request-volume protection. This issue is fixed in Echo v5.1.0.

[ Fixes ]Fixes and patches

• github.com/labstack/echo/v5 5.1.0Fixed version · GitHub Advisories · go package github.com/labstack/echo/v5: upgrade to 5.1.0 or later (affected < 5.1.0)

[ Packages ]Affected open-source packages

• github.com/labstack/echo/v5 goAffected < 5.1.0 · fixed in 5.1.0 · GHSA-246p-cpwv-v3jq
• github.com/labstack/echo/v4 goAffected >= 4.0.0, <= 4.16.2 · GHSA-246p-cpwv-v3jq

[ References ]References

• github.com/labstack/echo/commit/22e4b71109ef072ef011a489066ec662ca9565b2
• github.com/labstack/echo/releases/tag/v5.1.0
• github.com/labstack/echo/security/advisories/GHSA-246p-cpwv-v3jq