Echo: X-Real-IP extractor trusts the header value instead of the sending peer
Exact source revision recorded 24 Oct 2026 13:19:41 UTC. It does not establish the source's current position. Latest evidence.
osv · GHSA-h53f-rm2w-w7rg
Published## Impact In 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. Applications 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. ## Affected versions and patch All 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). The 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). ## Workarounds Use `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. ## Credits Reported 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.
- Source published
- 23 Oct 2026 20:50:25 UTC
- Source modified
- 23 Oct 2026 21:00:04 UTC
- Observed here
- 24 Oct 2026 13:19:41 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
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CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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