Vulnerability Description
Hono is a Web application framework that provides support for any JavaScript runtime. From 4.7.0 to 4.12.33, the Proxy Helper proxy() function in hono/proxy does not remove response headers named by the origin's Connection header. Per RFC 9110 Section 7.6.1, an intermediary must remove the header fields listed in a message's Connection header field before forwarding the message, in addition to the well known hop by hop headers, but the proxy() function only removed the well known hop by hop headers, including Connection itself, from origin responses. A client may therefore receive response headers that the origin intended only for its immediate peer, disclosing connection scoped or internal metadata contained in such headers, when an application proxies responses from an origin that declares additional, non standard headers as hop by hop via the Connection response header. This issue is fixed in version 4.12.34.
CVSS Score
LOW
Related Weaknesses (CWE)
References
- https://github.com/honojs/hono/commit/720b566290793d4358bf39843adcb7cf4da4548f
- https://github.com/honojs/hono/releases/tag/v4.12.34
- https://github.com/honojs/hono/security/advisories/GHSA-79qm-7rj5-m7r9
FAQ
What is CVE-2026-71849?
CVE-2026-71849 is a vulnerability with a CVSS score of 3.7 (LOW). Hono is a Web application framework that provides support for any JavaScript runtime. From 4.7.0 to 4.12.33, the Proxy Helper proxy() function in hono/proxy does not remove response headers named by t...
How severe is CVE-2026-71849?
CVE-2026-71849 has been rated LOW with a CVSS base score of 3.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-71849?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.