Hono: Proxy Helper does not remove response headers listed in the `Connection` header

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-71849
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-07 19:18:54 UTC
Updated2026-08-07 19:18:54 UTC
DescriptionHono 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.

Risk And Classification

Primary CVSS: v3.1 3.7 LOW from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Problem Types: CWE-200 | CWE-200 CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1CNADECLARED3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Honojs Hono affected >= 4.7.0, < 4.12.34 Not specified

References

ReferenceSourceLinkTags
github.com/honojs/hono/security/advisories/GHSA-79qm-7rj5-m7r9 [email protected] github.com
github.com/honojs/hono/commit/720b566290793d4358bf39843adcb7cf4da4548f [email protected] github.com
github.com/honojs/hono/releases/tag/v4.12.34 [email protected] github.com
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