CVE-2026-54286
Medium
Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.25, 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 admin\secret.txt into a nested file under the root and serves it, letting an attacker read static files meant to be protected behind prefix-mounted middleware. This vulnerability is fixed in 4.12.25.
SeverityMedium
CVSS5.9
Exploit probability—
Product
Hono
PublishedJun 22, 2026
First seenJun 22, 2026
Weakness typeCWE-22Path traversal
How to fix
Update
- hono4.12.25 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| hononpm | v < 4.12.25 | 4.12.25 |
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