---
id: CVE-2026-118656
title: 'Echo: Open Redirect via Control-Character Prefix Defeating sanitizeURI'
summary: >-
  Echo is a Go web framework. Prior to 4.16.0 and 5.4.0, sanitizeURI checks only
  the first two bytes of a redirect target before deciding whether it begins
  with an absolute-path separator pair. When AddTrailingSlash or
  RemoveTrailingSlash …
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-601
vendor: labstack
product: echo
affected:
  - 'echo >= 5.0.0, < 5.4.0'
  - echo < 4.16.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-29T15:29:15.771728Z'
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T17:23:39.728Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118656'
references:
  - url: 'https://github.com/labstack/echo/security/advisories/GHSA-v753-g4cw-jm48'
    label: 'https://github.com/labstack/echo/security/advisories/GHSA-v753-g4cw-jm48'
  - url: >-
      https://github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1
    label: >-
      https://github.com/labstack/echo/commit/b838391e2eade87ae7e5a09d7bb5087bec271ec1
  - url: >-
      https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af
    label: >-
      https://github.com/labstack/echo/commit/fc410094b2f3415cf2bf5204082137b205bfd5af
  - url: 'https://github.com/labstack/echo/releases/tag/v4.16.0'
    label: 'https://github.com/labstack/echo/releases/tag/v4.16.0'
  - url: 'https://github.com/labstack/echo/releases/tag/v5.4.0'
    label: 'https://github.com/labstack/echo/releases/tag/v5.4.0'
  - url: 'https://github.com/advisories/GHSA-v753-g4cw-jm48'
  - url: 'https://github.com/labstack/echo'
tags:
  - cve.org
  - ghsa
  - go
  - osv
aliases:
  - GHSA-v753-g4cw-jm48
ecosystem: go
patched:
  - github.com/labstack/echo/v5 5.4.0
  - github.com/labstack/echo/v4 4.16.0
epss: 0.00197
epssPercentile: 0.09443
ingestedAt: '2026-10-28T21:18:49.948Z'
---

## Overview

Echo is a Go web framework. Prior to 4.16.0 and 5.4.0, sanitizeURI checks only the first two bytes of a redirect target before deciding whether it begins with an absolute-path separator pair. When AddTrailingSlash or RemoveTrailingSlash is configured with a redirect status, a slash, TAB, separator path form can evade the guard, be emitted in the Location header, and be normalized by a browser into an attacker-controlled host. This issue is fixed in 4.16.0 and 5.4.0.

## Affected

- `echo >= 5.0.0, < 5.4.0`
- `echo < 4.16.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-118656)

Affected packages:

- `github.com/labstack/echo/v5 < 5.4.0`
- `github.com/labstack/echo/v4 < 4.16.0`

Patched in:

- `github.com/labstack/echo/v5 5.4.0`
- `github.com/labstack/echo/v4 4.16.0`

Source: https://github.com/advisories/GHSA-v753-g4cw-jm48