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
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade nodejs-full-i18nUpgrade npmUpgrade nodejs-nodemonUpgrade v8-12.4-develUpgrade nodejs-packaging-bundlerUpgrade nodejs-docsUpgrade nodejsUpgrade nodejs-libsUpgrade nodejs-packagingUpgrade v8-13.6-develUpgrade nodejs-devel | Apr 16, 2026 | Apr 8, 2026 |
| Amazon_linux_2023 | — | Upgrade nodejs22-docsUpgrade nodejs24-develUpgrade nodejs22-npmUpgrade nodejs20-debugsourceUpgrade nodejs22Upgrade v8-12.4-develUpgrade v8-13.6-develUpgrade nodejs20-full-i18nUpgrade nodejs22-debugsourceUpgrade nodejs24Upgrade nodejs24-npmUpgrade nodejs22-libsUpgrade nodejs20-libs-debuginfoUpgrade nodejs24-debuginfoUpgrade nodejs24-libsUpgrade nodejs24-debugsourceUpgrade nodejs24-full-i18nUpgrade nodejs22-libs-debuginfoUpgrade nodejs20-develUpgrade nodejs20Upgrade nodejs22-full-i18nUpgrade nodejs20-libsUpgrade nodejs24-libs-debuginfoUpgrade nodejs22-develUpgrade v8-11.3-develUpgrade nodejs20-npmUpgrade nodejs20-debuginfoUpgrade nodejs24-docsUpgrade nodejs22-debuginfoUpgrade nodejs20-docs | Apr 7, 2026 | Mar 12, 2026 |
| Oracle_linux | — | Upgrade nodejs-packaging-bundlerUpgrade nodejs24Upgrade v8-13.6-develUpgrade nodejsUpgrade nodejs-develUpgrade nodejs-docsUpgrade nodejs24-libsUpgrade nodejs-packagingUpgrade nodejs24-full-i18nUpgrade nodejs24-develUpgrade nodejs24-npmUpgrade nodejs-libsUpgrade nodejs-full-i18nUpgrade nodejs-npmUpgrade nodejs24-docsUpgrade nodejs-nodemonUpgrade npmUpgrade v8-12.4-devel | Apr 22, 2026 | Mar 12, 2026 |
| Redhat_linux | — | Upgrade nodejs-nodemonUpgrade npmUpgrade v8-13.6-develUpgrade nodejs-npmUpgrade nodejs-full-i18nUpgrade nodejs-develUpgrade nodejsUpgrade nodejs-libs-debuginfoUpgrade nodejs24-docsUpgrade nodejs-docsUpgrade nodejs22-debuginfoUpgrade nodejs-libsUpgrade nodejs24-npmUpgrade nodejs24-develUpgrade nodejs24Upgrade nodejs24-libs-debuginfoUpgrade nodejs24-debugsourceUpgrade nodejs22-debugsourceUpgrade nodejs24-libsUpgrade nodejs24-debuginfoUpgrade nodejs-debugsourceUpgrade v8-12.4-develUpgrade nodejs-packaging-bundlerUpgrade nodejs-debuginfoUpgrade nodejs-packagingUpgrade nodejs24-full-i18n | Apr 9, 2026 | Mar 12, 2026 |
| Rocky_linux | — | Upgrade nodejs-libsUpgrade nodejs24-debugsourceUpgrade nodejs-debugsourceUpgrade nodejs22-debuginfoUpgrade nodejs-libs-debuginfoUpgrade nodejsUpgrade nodejs-full-i18nUpgrade nodejs-debuginfoUpgrade v8-13.6-develUpgrade v8-12.4-develUpgrade nodejs24Upgrade nodejs24-libs-debuginfoUpgrade npmUpgrade nodejs22-debugsourceUpgrade nodejs-npmUpgrade nodejs24-full-i18nUpgrade nodejs24-develUpgrade nodejs24-debuginfoUpgrade nodejs-develUpgrade nodejs24-libs | Apr 13, 2026 | Apr 10, 2026 |
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