Is there a public exploit for CVE-2026-126343?

No public exploit for CVE-2026-126343 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-126343?

CVE-2026-126343 scores CVSS 5.3 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0%.

What does CVE-2026-126343 affect?

CVE-2026-126343 affects honojs @hono/node-server.

5.3 Medium

@hono/node-server: Unhandled `ECONNRESET` on the socket during an asynchronous WebSocket upgrade crashes the process

CVE-2026-126343

Summary While @hono/node-server waits for the Hono application to handle a WebSocket upgrade request, the socket has no error listener. If the client resets the TCP connection during that time, the resulting ECONNRESET is emitted as an unhandled 'error' event and the process terminates. Details The upgrade handler awaits the application before attaching any listener to the socket. When middleware on the upgrade path does asynchronous work, such as an authentication lookup, a connection reset in that window has no handler. If a global uncaughtException handler swallows the error, the pending upgrade is never released and its entry is retained for the lifetime of the process. The fix attaches error and close listeners to the socket before calling the application, releases the pending upgrade when the socket closes, and skips the handshake on a destroyed socket. Impact An unauthenticated client can terminate the server process with a single connection by sending a WebSocket upgrade request and resetting the connection before the application has responded. Where the crash is suppressed, repeated requests grow the heap. This affects applications that enable WebSocket support in…

Assessment

CVSS: 5.3 (v3.1)
Severity: Medium
EPSS: 0% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 12 November 2026
Last updated: 13 November 2026
Affected: honojs · node-server · @hono/node-server
Weakness: CWE-248
Assigner: GitHub_M

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

At the source

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