CVE-2026-28807

Summary

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 Software

VendorProductVersion RangeStatus
gleam-wispwisp2.1.1 < 2.2.1affected
gleam-wispwisp129dcb1fe10ab1e676145d91477535e1c90ab550 < 161118c431047f7ef1ff7cabfcc38981877fdd93affected

Weaknesses

  • CWE-22: CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References