npm · hono
Hono: Proxy Helper does not remove response headers listed in the `Connection` header
The Proxy Helper (hono/proxy) does not remove response headers named by the origin's Connection header. Headers that the origin marked as connection-scoped are therefore forwarded to clients.
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. The proxy() function removed the well-known hop-by-hop headers (including Connection itself) from origin responses, but did not remove the headers that the response's Connection header field designated as connection-scoped.
This issue arises when an application proxies responses from an origin that declares additional, non-standard headers as hop-by-hop via the Connection response header.
A client may receive response headers that the origin intended only for its immediate peer. This may lead to:
This issue affects applications that use the Proxy Helper (hono/proxy) to forward responses from origins that list custom header names in their Connection response header. Applications whose origins only use the standard hop-by-hop headers are not affected.
Is your project exposed to this? Stateward checks every dependency on every pull request and flags it only if your code actually reaches it.
Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.