CVE-2026-39408 PUBLISHED

Hono has a path traversal in toSSG() allows writing files outside the output directory

Assigner: GitHub_M
Reserved: 07.04.2026 Published: 08.04.2026 Updated: 08.04.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 5.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	None	Confidentiality	None
Attack Complexity	High	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	honojs
Product	hono
Versions	Version < 4.12.12 is affected

References

Problem Types

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CWE