Is there a public exploit for CVE-2026-39408?

No public exploit for CVE-2026-39408 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-39408?

CVE-2026-39408 scores CVSS 5.9 (v4.0), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.51%.

What does CVE-2026-39408 affect?

CVE-2026-39408 affects honojs hono.

5.9 Medium

Hono is a Web application framework that provides support for any JavaScript runtime.

CVE-2026-39408

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.12, a path traversal issue in toSSG() allows files to be written outside the configured output directory during static site generation. When using dynamic route parameters via ssgParams, specially crafted values can cause generated file paths to escape the intended output directory. This vulnerability is fixed in 4.12.12.

Assessment

CVSS: 5.9 (v4.0)
Severity: Medium
EPSS: 0.51% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 8 April 2026
Last updated: 24 July 2026
Affected: honojs · hono
Weakness: CWE-22
Assigner: security-advisories@github.com

CVSS vectorCVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

At the source

References

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