Vulnerability Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.34, the built-in CORS middleware, hono/cors, is vulnerable to a regular expression denial of service (ReDoS). During a preflight OPTIONS request, the middleware parses the attacker-controlled Access-Control-Request-Headers header using a whitespace-tolerant regular expression whose backtracking makes its running time quadratic in the input length. Because the header value is bounded only by the deployment's maximum HTTP header size, a single preflight carrying a long run of whitespace can consume seconds of CPU and block request processing. On runtimes that share one execution thread across requests, this stalls concurrent requests as well, and repeated requests can render the service unresponsive. This affects the default configuration, since the vulnerable path is reached whenever cors() is used with an unset or empty allowHeaders. Applications that set a non-empty allowHeaders are not affected. This issue is fixed in version 4.12.34.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/honojs/hono/commit/93fc250d8b4df58ea542cb945171de8013d5e6d5
- https://github.com/honojs/hono/releases/tag/v4.12.34
- https://github.com/honojs/hono/security/advisories/GHSA-8j4g-w8fx-2239
FAQ
What is CVE-2026-69207?
CVE-2026-69207 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.34, the built-in CORS middleware, hono/cors, is vulnerable to a regular expression denial of service...
How severe is CVE-2026-69207?
CVE-2026-69207 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-69207?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.