Vulnerability · Published Mar 10, 2026 · Assigned by EEF
CVE-2026-28807Path Traversal in wisp.serve_static allows arbitrary file read
High 8.7
In plain English
A high-severity path traversal in wisp from gleam-wisp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 67% of all known vulnerabilities).
Official description
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in gleam-wisp wisp allows arbitrary file read via percent-encoded path traversal. The wisp.serve_static function is vulnerable to path traversal because sanitization runs before percent-decoding. The encoded sequence %2e%2e passes through string.replace unchanged, then uri.percent_decode converts it to .., which the OS resolves as directory traversal when the file is read. An unauthenticated attacker can read any file readable by the application process in a single HTTP request, including application source code, configuration files, secrets, and system files. This issue affects wisp: from 2.1.1 before 2.2.1.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| gleam-wisp | wisp | 2.1.1 – before 2.2.1 |
| gleam-wisp | wisp | 129dcb1fe10ab1e676145d91477535e1c90ab550 – before 161118c431047f7ef1ff7cabfcc38981877fdd93 |
Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N