# CVE-2026-118651: Echo Proxy middleware IP spoofing via X-Real-IP header

Source: https://junglewise.ai/threats/cve-2026-118651-echo-is-a-go-web-framework-from-4-0-0-until-5-4-0-the-proxy  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-28. Updated: 2026-10-28  
License: CC BY 4.0 with a link back

CVE-2026-118651 · Severity: medium · CVSS 5.3 · Published 2026-10-28

Echo is a Go web framework used to build web services and APIs. The Proxy middleware component can forward a client-supplied X-Real-IP header to upstream services without validation, allowing attackers to spoof their client IP address. This undermines IP-based security controls such as access restrictions, rate limiting, audit logging, and geographic blocking that upstream services rely on.

Technologies: [github.com/labstack/echo/v4 (Go)](https://junglewise.ai/threats/technologies/github-com-labstack-echo-v4), [github.com/labstack/echo/v5 (Go)](https://junglewise.ai/threats/technologies/github-com-labstack-echo-v5), [Labstack Echo](https://junglewise.ai/threats/technologies/labstack-echo). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [Labstack](https://junglewise.ai/threats/vendors/labstack).

## Quick answers

**Is CVE-2026-118651 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-118651 being exploited in the wild.

**How severe is CVE-2026-118651?** Medium severity, with a CVSS score of 5.3, published 28 October 2026.

**Which products and versions are affected?** github.com/labstack/echo/v4 (Go) >= 4.0.0, <= 4.16.2, SEMVER:introduced=4.0.0, SEMVER:introduced=4.0.0,last_affected=4.16.2; github.com/labstack/echo/v5 (Go) < 5.4.0, SEMVER:introduced=0,fixed=5.4.0; Labstack Echo 4.0.0 to 5.3.x.

**Is there a fix for CVE-2026-118651?** Yes. github.com/labstack/echo/v5 (Go): upgrade to 5.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-118651 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-118651?** Check whether you run github.com/labstack/echo/v4 (Go), github.com/labstack/echo/v5 (Go) or Labstack Echo at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/labstack/echo/v5 (Go): upgrade to 5.4.0 or later

  ```sh
  go get github.com/labstack/echo/v5@v5.4.0
  ```


## Technical details

The Proxy middleware in Echo versions 4.0.0 through 5.3.x preserved attacker-supplied X-Real-IP headers and forwarded them upstream when Echo#IPExtractor was not configured. An unauthenticated remote attacker can inject a spoofed X-Real-IP header in requests, causing upstream services to record a false client IP address. The fix in v5.4.0 ensures the Proxy middleware always derives X-Real-IP from Context.RealIP() instead of forwarding client-controlled values.

## Affected products

- labstack Echo 4.0.0 to 5.3.x

## Identifiers

- CVE-2026-118651
- GHSA-99jh-6h7p-pp36
- GO-2026-6875

## Timeline

- 2026-10-28: disclosed
- 2026-09-27: patched

## References

- [https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af](https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af)
- [https://github.com/labstack/echo/releases/tag/v5.4.0](https://github.com/labstack/echo/releases/tag/v5.4.0)

## Related threats

- [Echo web framework arbitrary URI scheme redirect](https://junglewise.ai/threats/cve-2026-118658-echo-is-a-go-web-framework-prior-to-4-15-2-and-5-1-1-context)
- [Echo Go web framework scheme header spoofing and HSTS bypass](https://junglewise.ai/threats/cve-2026-118657-echo-is-a-go-web-framework-prior-to-4-16-0-and-5-4-0-context)
- [Echo open redirect in sanitizeURI with trailing slash redirect](https://junglewise.ai/threats/cve-2026-118656-echo-is-a-go-web-framework-prior-to-4-16-0-and-5-4-0-sanitizeuri)
- [Echo path traversal via double URL encoding in Static middleware](https://junglewise.ai/threats/cve-2026-118655-echo-is-a-go-web-framework-prior-to-4-15-3-and-5-2-0-middleware)
- [Echo path traversal in static file handlers via dot segment normalization](https://junglewise.ai/threats/cve-2026-118654-echo-is-a-go-web-framework-prior-to-4-16-0-and-5-4-0-echo-s)