Path traversal in hono - CVE-2026-54286
Published: July 21, 2026
Vulnerability identifier: #VU138923
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-54286
CWE-ID: CWE-22
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Hono
Affected software:
hono
hono
Detailed vulnerability description
The vulnerability allows a remote attacker to perform directory traversal attacks.
The vulnerability exists due to on Windows hosts, an encoded backslash (%5C) in the request path decodes to , which the Windows path resolver treats as a separator. serve-static then resolves a single URL segment such as adminsecret.txt into a nested file under the root and serves it. A remote attacker can send a specially crafted HTTP request and read static files meant to be protected behind prefix-mounted middleware.
How to mitigate CVE-2026-54286
Install updates from vendor's website.