Wednesday, November 11, 2026 Security Releases

The Node.js Project Security releases available

Updates are now available for the 26.x, 24.x, 22.x Node.js release lines for the following issues.

Patched vulnerabilities

This security release includes the following dependency updates to address public vulnerabilities:

• llhttp on 22.x, 24.x, 26.x
• undici on 24.x, 26.x
• sqlite on 22.x, 24.x

HTTP/2: remote abort, CHECK_EQ(current_nghttp2_memory_, 0) in ~Http2Session() (CVE-2026-123863) - (high)

A reachable assertion in Node.js HTTP/2 session teardown lets any unauthenticated client abort the server, over both TLS and cleartext. A client can arrange for an Http2Stream that still holds nghttp2-allocated header buffers to outlive its session: the stream is removed from the session's stream set but never detached, so when ~Http2Session() runs the memory accounting is nonzero and the CHECK_EQ(current_nghttp2_memory_, 0) assertion fails, terminating the process.

The trigger needs only a default http2 server whose handler responds before the request body has ended, which is typical. It is a variant of CVE-2024-27983 that the earlier fix did not cover, because that fix only detached streams still tracked in the session.

Impact:

• This vulnerability affects all users in active release lines: 24.x, 26.x

Thank you, to Chris Rohlf in collaboration with Claude and Anthropic Research for reporting this vulnerability and thank you mcollina for fixing it.

HTTPS: a zero-length TLS write re-enters llhttp_execute(), and the server copies its own heap into the request body (CVE-2026-123864) - (high)

A re-entrancy flaw in Node.js HTTPS lets an unauthenticated client read memory belonging to other connections, including TLS private keys and other users' requests. TLSWrap::DoWrite() calls ClearOut() directly when asked to write zero bytes; if that write is issued from JavaScript running inside the HTTP parser's on_body callback, ClearOut() decrypts the next TLS record while the parser is still mid-body, re-entering llhttp_execute() and causing a use-after-free and an out-of-bounds heap read. The server then copies that freed or unrelated heap memory into the response for the request body.

Triggering it requires a handler that calls res.flushHeaders() before the request body ends and later calls res.end() with a non-empty chunk, and reading the leaked memory requires any ordinary route that echoes or stores a request body. Cleartext node:http is not affected.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to Chris Rohlf in collaboration with Claude and Anthropic Research for reporting this vulnerability and thank you mcollina for fixing it.

HTTP/2 sessions never clean up if a protocol error is triggered during connection shutdown (CVE-2026-123865) - (high)

An unauthenticated HTTP/2 client can permanently leak Node.js server memory and file descriptors. If a peer triggers a protocol error, for example an oversized frame header, while the session is already shutting down, nghttp2 tears the session down internally but Node.js never notices, leaving a dangling session: the socket stays in CLOSE_WAIT and all of Node.js HTTP/2 state for that connection is held in memory indefinitely, with no further cost to the attacker.

The attacker can start the shutdown remotely by sending GOAWAY(NO_ERROR), so it is reliable against default HTTP/2 servers. It is an incomplete-fix case of CVE-2026-48937: that fix detected nghttp2 internal terminations by watching for GOAWAY sent while not shutting down, but missed terminations that arrive while the session is already shutting down.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to pimterry for reporting this vulnerability and thank you mcollina for fixing it.

HTTP/2 stream teardown can send freed response memory to the peer (CVE-2026-123866) - (high)

A use-after-free in Node.js HTTP/2 stream teardown can leak response memory, including the contents of other connections' response buffers, to a peer. When a stream is torn down while a write is still backpressured, for example by a peer RST_STREAM or by the server's own per-stream timeout destroying the stream, the stream's response buffer is freed but a reference to it is still used, so freed or unrelated heap memory is written to the socket instead of the intended response.

On Node.js 26.x and 24.x the teardown can be driven purely by a remote peer once the window-size change from 26.9.0 and 24.22.0 is present, and on all supported lines the same defect is reachable through an application-initiated teardown such as a per-stream idle timeout.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to aidan02 for reporting this vulnerability and thank you mcollina for fixing it.

Node.js is vulnerable to a remotely triggerable uncaught exception in TLS servers via deferred handshake callbacks (CVE-2026-126051) - (high)

A deferred-callback use-after-destroy in Node.js TLS server handshake handling allows a remote, unauthenticated attacker to terminate the server process. When a TLS server uses any of the SNICallback, OCSPRequest, newSession, or resumeSession hooks, or server.addContext(), the corresponding OpenSSL callbacks are deferred, and the deferred code does not handle the underlying socket being destroyed between scheduling and execution.

By sending a client hello that reaches the vulnerable path (for example, no SNI together with an OCSP request) followed by padding and a socket FIN, an attacker makes OpenSSL deliver the client hello and the end-of-file in the same tick, so the socket is destroyed before the deferred callback runs and the process raises an uncaught exception instead of emitting an 'error' event.

Impact:

• This vulnerability affects all users in active release lines: 24.x, 26.x

Thank you, to pimterry for reporting this vulnerability and for fixing it.

TLS 1.2 renegotiation allows clients to change servername unilaterally to bypass client certificate authentication (CVE-2026-123872) - (high)

A client certificate authentication bypass in Node.js TLS lets a client change the servername during TLS 1.2 renegotiation to reach endpoints it was not authorized for. On a server that applies different client-certificate policies per hostname, for example stricter admin-only client-cert auth on one host and ordinary client-cert auth on another, a client that authenticates for a permitted host can renegotiate the TLS 1.2 connection under a different servername and carry its existing authentication to the protected host, bypassing the stricter policy.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to pimterry for reporting this vulnerability and for fixing it.

HTTP/2: use-after-free of Http2Stream when a respondWithFile() stream is reset during a pending write (CVE-2026-123874) - (high)

A use-after-free in Node.js HTTP/2 lets an unauthenticated client corrupt server memory, over both TLS and cleartext, when the server serves files with respondWithFile() or respondWithFD(). A client can make the server free an Http2Stream while a write request that points to it is still queued on the socket; when that write completes, the code dereferences and makes a virtual call through the freed object.

The only precondition is that the application serves a file with stream.respondWithFile() or stream.respondWithFD(), with default settings otherwise.

Impact:

• This vulnerability affects all users in active release lines: 24.x, 26.x

Thank you, to Chris Rohlf in collaboration with Claude and Anthropic Research for reporting this vulnerability and thank you mcollina for fixing it.

Remote unauthenticated HTTP/2 heap-buffer-overflow in session.altsvc() with a long origin (CVE-2026-123828) - (medium)

A one-byte heap buffer overflow in Node.js HTTP/2 Alt-Svc handling lets a remote, unauthenticated attacker corrupt process memory. When an application passes an attacker-controlled value such as a request's :authority header to Http2Session.altsvc(), the AltSvc implementation in src/node_http2.cc allocates a buffer sized to the origin length and then writes it with a null terminator, placing one byte past the end of the allocation.

A single request carrying a long but syntactically valid :authority triggers the out-of-bounds write, which aborts the process and serves as a remote heap-corruption primitive.

Impact:

• This vulnerability affects all users in active release lines: 24.x, 26.x

Thank you, to zonduu for reporting this vulnerability and thank you mcollina for fixing it.

CA-only SNI client-CA overrides fail open to the default CA, bypassing per-host mTLS authorization (CVE-2026-123867) - (medium)

A per-host mutual-TLS authorization bypass in Node.js lets a client authorized for the default hostname reach a protected hostname it is not authorized for. When a TLS server assigns a hostname a different client-certificate CA with server.addContext(host, { ca: protectedCA }) but no server certificate in that SNI context, the per-host client CA is never installed and the handshake falls back to the default client CA.

In src/crypto/crypto_tls.cc, CertCbDone installs the SNI context's CA only when setSniContext succeeds, but setSniContext returns false for a context with no server certificate, so a CA-only SNI context silently keeps the default CA. A client holding a certificate trusted by the default CA, but not the protected CA, can therefore complete mTLS to the protected hostname and read its response even with requestCert and rejectUnauthorized enabled, while a client certified by the protected CA is rejected.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to aur0r4_glyph for reporting this vulnerability and thank you mcollina for fixing it.

HTTP/2 inbound data queued on an undrained stream is charged to no session budget, so maxSessionMemory neither bounds it nor refuses new streams (CVE-2026-123868) - (medium)

An unauthenticated HTTP/2 client can exhaust Node.js server memory because inbound data queued on an undrained stream is charged to no session budget. Each inbound data frame creates one JavaScript Buffer view in the receiving stream's readable queue, but nothing charges that queue to current_session_memory_: the socket read buffer is accounted only during parsing and released immediately, so whatever stays queued is accounted to nothing.

A peer that fills a stream's receive window with one-byte data frames pays about 10 wire bytes per frame while the server retains about 114 bytes per frame, so a single stream on one connection can retain hundreds of megabytes from tens of megabytes sent. maxSessionMemory neither bounds the growth nor refuses new streams, because Http2Session::CanAddStream gates admission on the same counter that never sees the queue.

Impact:

• This vulnerability affects all users in active release lines: 24.x, 26.x

Thank you, to jiri1234 for reporting this vulnerability and thank you mcollina for fixing it.

Proxy credentials disclosed in ERR_PROXY_INVALID_CONFIG error messages (CVE-2026-123871) - (medium)

Node.js discloses proxy credentials in ERR_PROXY_INVALID_CONFIG error messages. CVE-2026-48615 established that a proxy credential must not appear in a Node.js error message and redacted the username and password from ProxyConfig.href, but that fix missed four error paths in the same subsystem, one of them inside the same constructor, which interpolate the raw proxy URL, credentials included, into an ERR_PROXY_INVALID_CONFIG message.

The proxy URL comes from the environment, but the defect is the sink: a secret that Node.js redacts everywhere else is emitted verbatim into a much wider audience than the process environment, such as stderr, container logs, log aggregation, and crash reporting services.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to p-v-p for reporting this vulnerability and thank you mcollina for fixing it.

Certificate validation bypass in Node.js https.Agent via cross-policy TLS session reuse (CVE-2026-123877) - (medium)

A certificate validation bypass in Node.js https.Agent lets a cached TLS session authenticated under one CA policy be reused by a later request with a stricter policy. https.Agent.prototype.getName() assigns the same Agent and session-cache key to a request that omits ca and one that explicitly supplies ca: [], because an omitted value appends nothing to the key while an empty array stringifies to an empty string.

The two policies differ: omitting ca uses the default trust store, while supplying ca replaces it. Since they share a key, a TLS session authenticated under the broader default policy is handed to a new connection made under the later ca: [] policy, and TLS 1.3 session resumption carries the earlier authentication forward, so the second request reports authorized === true and transmits confidential data to a server its own CA policy would reject on a fresh connection.

Impact:

• This vulnerability affects all users in active release lines: 22.x, 24.x, 26.x

Thank you, to aegis1337 and mickeyjoe for reporting this vulnerability and thank you mcollina for fixing it.

HTTP/2: cancelling one respondWithFile() download crashes the server (NULL dereference in StreamPipe) (CVE-2026-123875) - (medium)

A NULL pointer dereference in Node.js HTTP/2 lets an unauthenticated client crash the server, over both TLS and cleartext, by cancelling file downloads. When the server serves a file with stream.respondWithFile() or stream.respondWithFD() and the client cancels the request, a StreamPipe used for the transfer is torn down in an order that leaves a NULL pointer which is then dereferenced, aborting the process.

No crafted frames are needed, and a handful of cancelled requests against a default file-serving handler is enou