Vulnerability · Published Feb 19, 2026 · Assigned by GitHub_M

CVE-2026-25766Echo has a Windows path traversal via backslash in middleware.Static default filesystem

Medium 5.3

In plain English

A medium-severity path traversal in echo from labstack. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 67.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/labstack/echo/v5	5.0.3	GHSA-pgvm-wxw2-hrv9
Go	github.com/labstack/echo/v5	5.0.3	GO-2026-4502

Affected products (as reported)

Vendor	Product	Versions
labstack	echo	>= 5.0.0, < 5.0.3

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9 x_refsource_CONFIRM
https://github.com/labstack/echo/pull/2891 x_refsource_MISC
https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1 x_refsource_MISC