Vulnerability · Published Jun 22, 2026 · Assigned by VulnCheck

CVE-2026-53779WebP Server Go < 0.15.0 Path Traversal via Backslash Encoding on Windows

High 7.5

In plain English

A high-severity path traversal in webp_server_go from webp-sh. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 51.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

WebP Server Go through 0.14.4 contains a path traversal vulnerability on Windows that allows unauthenticated attackers to read files outside the configured IMG_PATH directory by sending requests with percent-encoded backslashes (%5C) that bypass the path.Clean() sanitization in handler/router.go. Attackers can exploit the discrepancy between Go's forward-slash-only path normalization and Windows file system APIs that treat backslashes and forward slashes as equivalent to access arbitrary files on the host filesystem accessible to the server process.

Affected products (as reported)

Vendor	Product	Versions
webp-sh	webp_server_go	0 – before 0.15.0

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

References

Pull Request issue-tracking
Patch Commit patch
https://www.vulncheck.com/advisories/webp-server-go-path-traversal-via-backslash-encoding-on-windows third-party-advisory