Deno is a JavaScript, TypeScript, and WebAssembly runtime. Starting in version 1.35.1 and prior to version 1.36.3, a vulnerability in Deno's Node.js compatibility runtime allows for cross-session data contamination during simultaneous asynchronous reads from Node.js streams sourced from sockets or files. The issue arises from the re-use of a global buffer (BUF) in stream_wrap.ts used as a performance optimization to limit allocations during these asynchronous read operations. This can lead to data intended for one session being received by another session, potentially resulting in data corruption and unexpected behavior. This affects all users of Deno that use the node.js compatibility layer for network communication or other streams, including packages that may require node.js libraries indirectly. Version 1.36.3 contains a patch for this issue.
Affected: crates.io: deno
### Summary
A vulnerability in Deno's Node.js compatibility runtime allows for cross-session data contamination during simultaneous asynchronous reads from Node.js streams sourced from sockets or files. The issue arises from the re-use of a global buffer (BUF) in stream_wrap.ts used as a performance optimization to limit allocations during these asynchronous read operations. This can lead to data intended for one session being received by another session, potentially resulting in data corruption and unexpected behavior.
### Details
A bug in Deno's Node.js compatibility runtime results in data cross-reception during simultaneous asynchronous reads from Node.js network streams. When multiple independent network socket connections are involved, this vulnerability can be triggered. For instance, two separate server sockets that receive data from their respective client sockets and then echo the received data back to the client using Node.js streams may experience an issue where data from one socket may appear on another socket. Due to the improper isolation of the global buffer (`BUF`), data sent by one socket can end up being incorrectly received by another socket. Consequently, data intended for one session may be exposed to another session, potentially leading to data corruption and unexpected behavior.
This buffer was introduced as a performance optimization to avoid excessive allocations during network read operations.
In cases where the [net.Stream](https://nodejs.org…