Security Vulnerabilities
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
0.0
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
0.001
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
0.002
Published
2026-03-12
This is an uncontrolled resource consumption vulnerability (CWE-400) that can lead to Denial of Service (DoS).
In vulnerable Undici versions, when interceptors.deduplicate() is enabled, response data for deduplicated requests could be accumulated in memory for downstream handlers. An attacker-controlled or untrusted upstream endpoint can exploit this with large/chunked responses and concurrent identical requests, causing high memory usage and potential OOM process termination.
Impacted users are applications that use Undici’s deduplication interceptor against endpoints that may produce large or long-lived response bodies.
PatchesThe issue has been patched by changing deduplication behavior to stream response chunks to downstream handlers as they arrive (instead of full-body accumulation), and by preventing late deduplication when body streaming has already started.
Users should upgrade to the first official Undici (and Node.js, where applicable) releases that include this patch.
CVSS Score
5.9
EPSS Score
0.0
Published
2026-03-12
The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive.
The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.
CVSS Score
7.5
EPSS Score
0.0
Published
2026-03-12
Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.7.0 to 2.7.1, A command injection vulnerability exists in Deno's node:child_process polyfill (shell: true mode) that bypasses the fix for CVE-2026-27190. The two-stage argument sanitization in transformDenoShellCommand (ext/node/polyfills/internal/child_process.ts) has a priority bug: when an argument contains a $VAR pattern, it is wrapped in double quotes (L1290) instead of single quotes. Double quotes in POSIX sh do not suppress backtick command substitution, allowing injected commands to execute. An attacker who controls arguments passed to spawnSync or spawn with shell: true can execute arbitrary OS commands, bypassing Deno's permission system. This vulnerability is fixed in 2.7.2.
CVSS Score
8.1
EPSS Score
0.001
Published
2026-03-12
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.13 and 8.6.39, the OAuth2 authentication adapter does not correctly validate app IDs when appidField and appIds are configured. During app ID validation, a malformed value is sent to the token introspection endpoint instead of the user's actual access token. Depending on the introspection endpoint's behavior, this could either cause all OAuth2 logins to fail, or allow authentication from disallowed app contexts if the endpoint returns valid-looking data for the malformed request. Deployments using the OAuth2 adapter with appidField and appIds configured are affected. This vulnerability is fixed in 9.6.0-alpha.13 and 8.6.39.
CVSS Score
6.5
EPSS Score
0.0
Published
2026-03-12
Black is the uncompromising Python code formatter. Prior to 26.3.1, Black writes a cache file, the name of which is computed from various formatting options. The value of the --python-cell-magics option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations. Fixed in Black 26.3.1.
CVSS Score
7.5
EPSS Score
0.0
Published
2026-03-12
Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, a negative Content-Length value was converted to unsigned, treating it as an impossibly large length instead. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.
CVSS Score
6.5
EPSS Score
0.001
Published
2026-03-12
Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.
CVSS Score
6.5
EPSS Score
0.001
Published
2026-03-12