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 Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade nodejs-develUpgrade nodejs-docsUpgrade v8-13.6-develUpgrade nodejs-libsUpgrade nodejsUpgrade nodejs-packagingUpgrade nodejs-packaging-bundlerUpgrade v8-12.4-develUpgrade nodejs-nodemonUpgrade npmUpgrade nodejs-full-i18n | Apr 16, 2026 | Apr 8, 2026 |
| Amazon_linux_2023 | — | Upgrade nodejs24Upgrade nodejs20-full-i18nUpgrade nodejs22Upgrade nodejs22-docsUpgrade nodejs24-develUpgrade nodejs22-libsUpgrade nodejs24-npmUpgrade v8-12.4-develUpgrade nodejs24-libsUpgrade nodejs24-debugsourceUpgrade nodejs24-debuginfoUpgrade nodejs20-libs-debuginfoUpgrade nodejs20-develUpgrade nodejs22-debugsourceUpgrade nodejs22-libs-debuginfoUpgrade nodejs20-debugsourceUpgrade v8-13.6-develUpgrade nodejs24-full-i18nUpgrade nodejs22-npmUpgrade nodejs24-docsUpgrade nodejs22-debuginfoUpgrade nodejs20-docsUpgrade nodejs22-full-i18nUpgrade nodejs20-libsUpgrade nodejs20Upgrade nodejs24-libs-debuginfoUpgrade nodejs22-develUpgrade v8-11.3-develUpgrade nodejs20-npmUpgrade nodejs20-debuginfo | Apr 7, 2026 | Mar 12, 2026 |
| Oracle_linux | — | Upgrade nodejs24-develUpgrade nodejs24-libsUpgrade nodejs24Upgrade nodejs-packagingUpgrade nodejs-develUpgrade v8-13.6-develUpgrade nodejsUpgrade nodejs24-full-i18nUpgrade nodejs-docsUpgrade nodejs-packaging-bundlerUpgrade nodejs-nodemonUpgrade npmUpgrade v8-12.4-develUpgrade nodejs-full-i18nUpgrade nodejs24-npmUpgrade nodejs-npmUpgrade nodejs-libsUpgrade nodejs24-docs | Apr 22, 2026 | Mar 12, 2026 |
| Redhat_linux | — | Upgrade nodejs-debuginfoUpgrade nodejs-packaging-bundlerUpgrade nodejs24-debuginfoUpgrade nodejs24-libsUpgrade v8-12.4-develUpgrade nodejs24Upgrade nodejs-debugsourceUpgrade nodejs22-debugsourceUpgrade nodejs24-debugsourceUpgrade nodejs24-libs-debuginfoUpgrade nodejs24-full-i18nUpgrade nodejs-packagingUpgrade nodejs-full-i18nUpgrade nodejs-libsUpgrade nodejs24-docsUpgrade nodejs-nodemonUpgrade v8-13.6-develUpgrade npmUpgrade nodejsUpgrade nodejs-npmUpgrade nodejs-libs-debuginfoUpgrade nodejs24-develUpgrade nodejs-develUpgrade nodejs22-debuginfoUpgrade nodejs24-npmUpgrade nodejs-docs | Apr 9, 2026 | Mar 12, 2026 |
| Rocky_linux | — | Upgrade v8-12.4-develUpgrade nodejs24-libsUpgrade nodejs24Upgrade nodejs24-libs-debuginfoUpgrade v8-13.6-develUpgrade npmUpgrade nodejs-develUpgrade nodejs24-debuginfoUpgrade nodejs24-develUpgrade nodejs24-full-i18nUpgrade nodejs22-debugsourceUpgrade nodejs-debuginfoUpgrade nodejs-npmUpgrade nodejs-full-i18nUpgrade nodejs-debugsourceUpgrade nodejs22-debuginfoUpgrade nodejsUpgrade nodejs-libs-debuginfoUpgrade nodejs-libsUpgrade nodejs24-debugsource | Apr 13, 2026 | Apr 10, 2026 |
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