Vulnerability · Published Mar 4, 2026 · Assigned by GitHub_M

CVE-2026-29045Hono: Arbitrary file access via serveStatic vulnerability

High 7.5

In plain English

A high-severity security flaw in hono from honojs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 51.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to version 4.12.4, when using serveStatic together with route-based middleware protections (e.g. app.use('/admin/*', ...)), inconsistent URL decoding allowed protected static resources to be accessed without authorization. The router used decodeURI, while serveStatic used decodeURIComponent. This mismatch allowed paths containing encoded slashes (%2F) to bypass middleware protections while still resolving to the intended filesystem path. This issue has been patched in version 4.12.4.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	hono	4.12.4	GHSA-q5qw-h33p-qvwr

Affected products (as reported)

Vendor	Product	Versions
honojs	hono	< 4.12.4

Weakness: CWE-177 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr x_refsource_CONFIRM
https://github.com/honojs/hono/commit/6a0607a929d888893f0c91d92dce2fcfdb3662a3 x_refsource_MISC