Nodejs: Security Vulnerabilities
A flaw in Node.js Permission Model network enforcement leaves Unix Domain Socket (UDS) server operations without the required permission checks, while all comparable network paths correctly enforce them.
As a result, code running under `--permission` without `--allow-net` can create and expose local IPC endpoints, allowing communication with other processes on the same host outside of the intended network restriction boundary.
This vulnerability affects Node.js **25.x** processes using the Permission Model where `--allow-net` is intentionally omitted to restrict network access. Note that `--allow-net` is currently an experimental feature.
CVSS Score
5.3
EPSS Score
0.002
Published
2026-03-30
A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values.
Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x**.
CVSS Score
5.9
EPSS Score
0.004
Published
2026-03-30
A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but the Http2Session object is never cleaned up.
This vulnerability affects HTTP2 users on Node.js 20, 22, 24 and 25.
CVSS Score
5.3
EPSS Score
0.005
Published
2026-03-30
A flaw in Node.js Permission Model filesystem enforcement leaves `fs.realpathSync.native()` without the required read permission checks, while all comparable filesystem functions correctly enforce them.
As a result, code running under `--permission` with restricted `--allow-fs-read` can still use `fs.realpathSync.native()` to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-read` is intentionally restricted.
CVSS Score
3.3
EPSS Score
0.002
Published
2026-03-30
An incomplete fix for CVE-2024-36137 leaves `FileHandle.chmod()` and `FileHandle.chown()` in the promises API without the required permission checks, while their callback-based equivalents (`fs.fchmod()`, `fs.fchown()`) were correctly patched.
As a result, code running under `--permission` with restricted `--allow-fs-write` can still use promise-based `FileHandle` methods to modify file permissions and ownership on already-open file descriptors, bypassing the intended write restrictions.
This vulnerability affects **20.x, 22.x, 24.x, and 25.x** processes using the Permission Model where `--allow-fs-write` is intentionally restricted.
CVSS Score
3.3
EPSS Score
0.001
Published
2026-03-30
A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`.
When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`.
* This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**
CVSS Score
7.5
EPSS Score
0.25
Published
2026-03-30
A flaw in Node.js URL processing causes an assertion failure in native code when `url.format()` is called with a malformed internationalized domain name (IDN) containing invalid characters, crashing the Node.js process.
CVSS Score
5.7
EPSS Score
0.003
Published
2026-03-30
ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to:
* Inject arbitrary HTTP headers
* Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)
The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:
// lib/dispatcher/client-h1.js:1121
if (upgrade) {
header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n`
}
CVSS Score
4.6
EPSS Score
0.003
Published
2026-03-12
ImpactA server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process.
Patches
Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-03-12
ImpactThe undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination.
The vulnerability exists because:
* The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15
* The createInflateRaw() call is not wrapped in a try-catch block
* The resulting exception propagates up through the call stack and crashes the Node.js process
CVSS Score
7.5
EPSS Score
0.009
Published
2026-03-12