Echo is a Go web framework. Prior to 4.15.3 and 5.2.0, middleware.Static can decode an already decoded Request.URL.Path a second time. Double-encoded separators can consequently be reconstructed before filesystem resolution. This can reach a file under a guarded route when the static middleware is registered globally. This issue is fixed in 4.15.3 and 5.2.0.
https://github.com/labstack/echo/security/advisories/GHSA-xwq5-6cqp-vx96
https://github.com/labstack/echo/releases/tag/v5.2.0
https://github.com/labstack/echo/releases/tag/v4.15.3
https://github.com/labstack/echo/pull/3006
https://github.com/labstack/echo/issues/2599
https://github.com/labstack/echo/commit/c3fa2a27ff92b2b8db360de614f999ef1da24725
https://github.com/labstack/echo/commit/a9ede66a5a7196411131beb1ee801e75bbaf7ac6