{"id":"GHSA-h53f-rm2w-w7rg","summary":"Echo: X-Real-IP extractor trusts the header value instead of the sending peer","details":"## Impact\n\nIn Echo v5, `ExtractIPFromRealIPHeader` checked whether the address supplied in `X-Real-IP` belonged to a trusted range instead of checking the address of the direct network peer. An untrusted client could therefore supply a loopback or private address and have it returned by `c.RealIP()` with the extractor's default trust options.\n\nApplications using this extractor for IP allowlists, IP-based rate limiting, audit logs or forwarding headers could accept a spoofed client identity. Exploitation requires that the attacker can reach Echo directly or that an intervening proxy passes through the attacker's `X-Real-IP` value. Applications using the default direct IP extractor are unaffected. Echo v4 is unaffected by this v5 regression.\n\n## Affected versions and patch\n\nAll v5 releases from v5.0.0 through v5.4.0 are affected. Upgrade to [v5.4.1](https://github.com/labstack/echo/releases/tag/v5.4.1).\n\nThe patch validates the direct peer before accepting a syntactically valid `X-Real-IP` value, restoring the v4 trust model. [Fix commit](https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec).\n\n## Workarounds\n\nUse `ExtractIPDirect` until upgrading, or ensure that only trusted proxies can reach Echo and that they replace client-supplied forwarding headers. Configure trusted proxy ranges narrowly for the deployment.\n\n## Credits\n\nReported and patched by @rm-Umar. @Duodum independently reported the same issue in GHSA-c3r7-8j36-7mx8, which is tracked as a duplicate of this advisory.","modified":"2026-10-23T21:00:04.309169447Z","published":"2026-10-23T20:50:25Z","database_specific":{"cwe_ids":["CWE-348"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-10-23T20:50:25Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/labstack/echo/security/advisories/GHSA-h53f-rm2w-w7rg"},{"type":"WEB","url":"https://github.com/labstack/echo/commit/1855061e572ae9dab727c811d8382f266bfbaaec"},{"type":"PACKAGE","url":"https://github.com/labstack/echo"},{"type":"WEB","url":"https://github.com/labstack/echo/releases/tag/v5.4.1"}],"affected":[{"package":{"name":"github.com/labstack/echo/v5","ecosystem":"Go","purl":"pkg:golang/github.com/labstack/echo/v5"},"ranges":[{"type":"SEMVER","events":[{"introduced":"5.0.0"},{"fixed":"5.4.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-h53f-rm2w-w7rg/GHSA-h53f-rm2w-w7rg.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}