Authorization Bypass Through User-Controlled Key Affecting github.com/valyala/fasthttp package, versions <1.70.0
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Start learning- Snyk IDSNYK-GOLANG-GITHUBCOMVALYALAFASTHTTP-19256953
- published25 Aug 2026
- disclosed18 Aug 2026
- creditAli Firas
Introduced: 18 Aug 2026
New CVE NOT AVAILABLE CWE-639 Â (opens in a new tab)Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade github.com/valyala/fasthttp to version 1.70.0 or higher.
Overview
github.com/valyala/fasthttp is a fast HTTP server and client API.
Affected versions of this package are vulnerable to Authorization Bypass Through User-Controlled Key via the ServeFile and ServeFS functions. An attacker can bypass access controls by submitting double-encoded path variants, which are decoded and interpreted as valid filesystem paths, allowing unauthorized access to protected files.