CVE-2026-118266 Echo: CSRF Protection Bypass via MethodOverride Rewriting POST to Safe Method

What is CVE-2026-118266?

CVE-2026-118266 is a medium-severity vulnerability in labstack echo, published on 28 Oct 2026.

Official description

Echo is a Go web framework. Prior to 4.16.0 and 5.4.0, Echo's MethodOverride middleware accepts a safe HTTP method as the override target for a POST request. When MethodOverride is registered before CSRF in the post-routing middleware chain, route selection retains the original state-changing POST handler but the override changes the method before CSRF evaluates it, causing both token validation and Sec-Fetch-Site checks to be skipped. A cross-site exploit requires an authenticated victim and an override value that a browser-submitted request can control, such as the form getter used by the advisory reproducer; the default X-HTTP-Method-Override header getter is not settable by a cross-site form. This issue is fixed in 4.16.0 and 5.4.0.

Weakness: CWE-352

Which versions are affected by CVE-2026-118266?

4 open source packages ship an affected version, including github.com/labstack/echo/v4 and github.com/labstack/echo/v5.

How do I fix CVE-2026-118266?

Upgrade github.com/labstack/echo/v4 to 4.16.0 or later.

Is CVE-2026-118266 being exploited?

There is no known exploitation of CVE-2026-118266 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-118266, ECHO-694f-e8ff-4ea6, GHSA-r7w9-592q-9vg4, UBUNTU-CVE-2026-118266.