FKIE_CVE-2026-25766

Vulnerability from fkie_nvd - Published: 2026-02-19 16:27 - Updated: 2026-02-23 20:17
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Summary
Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo’s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\` as a path separator, so `..\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\` as a path separator and resolves `..\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue.
References
security-advisories@github.comhttps://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1Patch
security-advisories@github.comhttps://github.com/labstack/echo/pull/2891Issue Tracking, Patch
security-advisories@github.comhttps://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9Exploit, Vendor Advisory
Impacted products
Vendor Product Version
labstack echo *
microsoft windows -
To clipboard 

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      "value": "Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo\u2019s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\\` as a path separator, so `..\\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\\` as a path separator and resolves `..\\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue."
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  "id": "CVE-2026-25766",
  "lastModified": "2026-02-23T20:17:51.353",
  "metrics": {
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