undici vulnerable to Denial of Service via TLS 1.2 certificate-changing renegotiation

Impact undici crashes the client process when a TLS 1.2 server renegotiates after the connection is established and presents a different, CA-trusted certificate whose hostname does not match the requested host. Node.js re-runs hostname verification on the renegotiated handshake and destroys the socket with ERRTLSCERTALTNAMEINVALID. undici's established socket error handler asserted that this error code could never occur, so the peer-controlled error became an uncaught AssertionError that terminates the Node.js process. Both the HTTP/1.1 and HTTP/2 paths are affected. A malicious or compromised HTTPS endpoint reached through undici or the global fetch() can crash the client with a single server-initiated renegotiation, taking down all in-flight requests and background work in the process. Only TLS 1.2 is affected, because TLS 1.3 does not support renegotiation. Exploitation does not require a CA compromise: the attacker controls the endpoint and can present two ordinary valid certificates, the first matching the requested URL and the second intentionally not matching it. Patches Upgrade to undici 6.29.1, 7.30.1, or 8.12.2. Workarounds Restrict outbound connections to TLS 1.3, for…

curl https://cve.zerocrew.in/api/cve/CVE-2026-87018