What’s Vulnerable › Vulnerabilities

CVE-2026-28807: Path Traversal in wisp.serve_static allows arbitrary file read

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-10 · updated 2026-06-17
• Weakness: CWE-22

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

• gleam-wisp wisp: from 2.1.1 before 2.2.1 — fixed in 2.2.1

How to fix

Upgrade to a fixed version: gleam-wisp wisp 2.2.1. Check the vendor advisory for mitigations.

References

• https://cna.erlef.org/cves/CVE-2026-28807.html
• https://github.com/gleam-wisp/wisp/commit/161118c431047f7ef1ff7cabfcc38981877fdd93
• https://github.com/gleam-wisp/wisp/security/advisories/GHSA-h7cj-j2vv-qw8r
• https://osv.dev/vulnerability/EEF-CVE-2026-28807

Get alerted when CVE-2026-28807 or the next vulnerability affects your stack