Improper Handling of URL Encoding (Hex Encoding) in hono - CVE-2026-29045
Published: July 24, 2026
Vulnerability identifier: #VU139314
CSH Severity: Medium
CVSS v4: 8.7 [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]
CVE-ID: CVE-2026-29045
CWE-ID: CWE-177
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper handling of url encoding in the serveStatic handler and routing layer when handling requests for protected static resources. A remote attacker can send a specially crafted request containing encoded slashes to disclose sensitive information.
This only affects applications that protect subpaths using route-based middleware and serve files from the same static root using serveStatic. The issue does not allow access outside the static root.
Affected software
hono
How to mitigate CVE-2026-29045
Install security update from vendor's website.
hono - update to 4.12.4