CVEvulnerability

CVE-2026-48126

8.2 HIGH Published 2026-05-26 Modified 2026-07-24 Official page ↗
Status
Deferred
Published
2026-05-26
Last modified
2026-07-24
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.2 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Weaknesses
CWE-22, CWE-23, CWE-644

Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.8, when algernon is started with --domain (or --letsencrypt, which silently turns on --domain at engine/flags.go:372), the request handler resolves the served directory by joining the configured --dir with the value of the client-supplied Host header. The join is performed by filepath.Join with no validation, so a Host: .. header walks one level above the document root. Subsequent file resolution then exposes everything in that parent directory — arbitrary file read, full directory listing, and, if any .lua file is present, server-side Lua execution. This vulnerability is fixed in 1.17.8.

Related

Weakness · CWE (3)

  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory weakness
  • CWE-23 Relative Path Traversal weakness
  • CWE-644 Improper Neutralization of HTTP Headers for Scripting Syntax weakness

References