What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-04 · updated 2026-06-17
• Weakness: CWE-177

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 products

• honojs hono: before 4.12.4 — fixed in 4.12.4

How to fix

Upgrade to a fixed version: honojs hono 4.12.4. Check the vendor advisory for mitigations.

References

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

Get alerted when CVE-2026-29045 or the next vulnerability affects your stack