# Echo: X-Real-IP extractor trusts the header value instead of the sending peer

Advisory record · `GHSA-h53f-rm2w-w7rg`

- **Identifiers:** `GHSA-h53f-rm2w-w7rg` · `CVE-2026-118265` · `GO-2026-6841`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-348](https://cwe.mitre.org/data/definitions/348.html)
- **Tags:** [CWE-348](https://agentprime.io/advisories/tag/cwe-348.md)
- **Published:** 23 Oct 2026
- **Updated:** 5 Nov 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 23 Oct 2026, 20:50 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/labstack/echo/v5` (Go): affected `>=5.0.0, <5.4.1`; fixed in `5.4.1`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Echo v5 (github.com/labstack/echo/v5) versions 5.0.0 through 5.4.0 are affected. The ExtractIPFromRealIPHeader extractor checks whether the X-Real-IP value is in a trusted range instead of checking the direct network peer, so a remote client that can reach Echo directly, or reach it through a proxy that passes the header on, can make c.RealIP() return a spoofed loopback or private address. Upgrade to v5.4.1. Until then, use ExtractIPDirect or make sure only trusted proxies can reach Echo and that they overwrite client-supplied forwarding headers.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.3 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0014, the 3rd percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 28 Oct 2026, 19:17 UTC: [Confirmed by NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-118265)
- 31 Oct 2026, 14:11 UTC: First seen by agentprime
- 31 Oct 2026, 14:11 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-h53f-rm2w-w7rg)

## Sources

- [GitHub Advisory Database: GHSA-h53f-rm2w-w7rg](https://github.com/advisories/GHSA-h53f-rm2w-w7rg)
- [OSV: GHSA-h53f-rm2w-w7rg](https://osv.dev/vulnerability/GHSA-h53f-rm2w-w7rg)
- <https://github.com/labstack/echo/security/advisories/GHSA-h53f-rm2w-w7rg>
- <https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec>
- <https://github.com/labstack/echo>
- <https://github.com/labstack/echo/releases/tag/v5.4.1>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-h53f-rm2w-w7rg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-h53f-rm2w-w7rg/>. Everything for agents: <https://agentprime.io/llms.txt>.