GHSA-vxpw-j846-p89q

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GHSA-vxpw-j846-p89q

Summary: undici WebSocket client vulnerable to denial of service via fragment count bypass

Details: ## Impact The undici WebSocket client enforces `maxPayloadSize` on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (`new WebSocket(...)`) or the `WebSocketStream` API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. ## Patches Upgrade to undici v6.27.0, v7.28.0 or v8.5.0. ## Workarounds No workaround is available. The fix must be applied through an upgrade.

References: https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q, https://nvd.nist.gov/vuln/detail/CVE-2026-12151, https://cna.openjsf.org/security-advisories.html, https://github.com/nodejs/undici