Double Decoding of the Same Data in hono - #VU152732
Published: September 29, 2026
Vulnerability identifier: #VU152732
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-174
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass middleware protections for static files.
The vulnerability exists due to double decoding of the request path in the serveStatic middleware when handling a malformed percent-encoded request path. A remote attacker can send a crafted request that is routed as one path and resolved as another to bypass middleware protections for static files.
Only applications that mount middleware on a portion of the directory served by serveStatic are affected; files remain resolved within the configured root.
Affected software
hono
Remediation
Install security update from vendor's website.
hono - update to 4.13.11