CVE-2026-69207 json
Hono: ReDoS in CORS middleware via Access-Control-Request-Headers
published 2026-08-03 3 mo ago modified 2026-10-24 15 d ago also GHSA-8j4g-w8fx-2239 , EUVD-2026-54677
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 49%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm hono 4.12.34
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | hono | <4.12.34 |
4.12.34 |
Affected products
- honojs hono
Classification
- Weakness
-
- CWE-1333 Inefficient Regular Expression Complexity
References
Sources
- CVE List CVE-2026-69207
- GitHub Advisory GHSA-8j4g-w8fx-2239
- NVD CVE-2026-69207
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