We have identified a bug in Node.js error handling where "Maximum call stack size exceeded" errors become uncatchable when asynchooks.createHook() is enabled. Instead of reaching process.on('uncaughtException'), the process terminates, making the crash unrecoverable. Applications that rely on AsyncLocalStorage (v22, v20) or asynchooks.createHook() (v24, v22, v20) become vulnerable to denial-of-service crashes triggered by deep recursion under specific conditions.

A flaw in Node.js's permission model allows a file's access and modification timestamps to be changed via futimes() even when the process has only read permissions. Unlike utimes(), futimes() does not apply the expected write-permission checks, which means file metadata can be modified in read-only directories. This behavior could be used to alter timestamps in ways that obscure activity, reducing the reliability of logs. This vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.

A malformed HTTP/2 HEADERS frame with oversized, invalid HPACK data can cause Node.js to crash by triggering an unhandled TLSSocket error ECONNRESET. Instead of safely closing the connection, the process crashes, enabling a remote denial of service. This primarily affects applications that do not attach explicit error handlers to secure sockets, for example: server.on('secureConnection', socket => { socket.on('error', err => { console.log(err) }) })

A flaw in Node.js’s Permissions model allows attackers to bypass --allow-fs-read and --allow-fs-write restrictions using crafted relative symlink paths. By chaining directories and symlinks, a script granted access only to the current directory can escape the allowed path and read sensitive files. This breaks the expected isolation guarantees and enables arbitrary file read/write, leading to potential system compromise. This vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.

Node.js could allow a remote attacker to bypass security restrictions, caused by improper path traversal sequence sanitization. By using a path traversal attack, an attacker could exploit this vulnerability leading to filesystem permission model bypass.

Node.js could allow a remote attacker to traverse directories on the system. By monkey-patching Buffer internals, namely, Buffer.prototype.utf8Write, an attacker could send a specially crafted URL request containing "dot dot" sequences (/../) to read arbitrary files on the system.

Node.js could allow a remote attacker to bypass security restrictions, caused by the improper handling of wildcards in --allow-fs-read and --allow-fs-write. An attacker could exploit this vulnerability to gain access to the system.

Node.js could allow a local authenticated attacker to gain elevated privileges on the system, caused by a bug in the implementation of the exception of CAPNETBINDSERVICE. An attacker could exploit this vulnerability to inject code that inherits the process's elevated privileges.

A vulnerability in Node.js HTTP servers allows an attacker to send a specially crafted HTTP request with chunked encoding, leading to resource exhaustion and denial of service (DoS). The server reads an unbounded number of bytes from a single connection, exploiting the lack of limitations on chunk extension bytes. The issue can cause CPU and network bandwidth exhaustion, bypassing standard safeguards like timeouts and body size limits.

Node.js could allow a remote attacker to bypass security restrictions, caused by a path traversal bypass using non-Buffer Uint8Array objects. By sending a specially crafted request, an attacker could exploit this vulnerability to bypass the experimental permission model.

HTTP/2 Rapid reset attack The HTTP/2 protocol allows clients to indicate to the server that a previous stream should be canceled by sending a RSTSTREAM frame. The protocol does not require the client and server to coordinate the cancellation in any way, the client may do it unilaterally. The client may also assume that the cancellation will take effect immediately when the server receives the RSTSTREAM frame, before any other data from that TCP connection is processed.

Abuse of this feature is called a Rapid Reset attack because it relies on the ability for an endpoint to send a RSTSTREAM frame immediately after sending a request frame, which makes the other endpoint start working and then rapidly resets the request. The request is canceled, but leaves the HTTP/2 connection open.

The HTTP/2 Rapid Reset attack built on this capability is simple: The client opens a large number of streams at once as in the standard HTTP/2 attack, but rather than waiting for a response to each request stream from the server or proxy, the client cancels each request immediately.

The ability to reset streams immediately allows each connection to have an indefinite number of requests in flight. By explicitly canceling the requests, the attacker never exceeds the limit on the number of concurrent open streams. The number of in-flight requests is no longer dependent on the round-trip time (RTT), but only on the available network bandwidth.

In a typical HTTP/2 server implementation, the server will still have to do significant amounts of work for canceled requests, such as allocating new stream data structures, parsing the query and doing header decompression, and mapping the URL to a resource. For reverse proxy implementations, the request may be proxied to the backend server before the RSTSTREAM frame is processed. The client on the other hand paid almost no costs for sending the requests. This creates an exploitable cost asymmetry between the server and the client.

Multiple software artifacts implementing HTTP/2 are affected. This advisory was originally ingested from the swift-nio-http2 repo advisory and their original conent follows.

swift-nio-http2 specific advisory swift-nio-http2 is vulnerable to a denial-of-service vulnerability in which a malicious client can create and then reset a large number of HTTP/2 streams in a short period of time. This causes swift-nio-http2 to commit to a large amount of expensive work which it then throws away, including creating entirely new Channels to serve the traffic. This can easily overwhelm an EventLoop and prevent it from making forward progress.

swift-nio-http2 1.28 contains a remediation for this issue that applies reset counter using a sliding window. This constrains the number of stream resets that may occur in a given window of time. Clients violating this limit will have their connections torn down. This allows clients to continue to cancel streams for legitimate reasons, while constraining malicious actors.