PT-2026-60253 · Websocket · Ws

George Chen · Published 2026-07-15 · Updated 2026-07-15 · CVE-2026-62389

NVD

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

ws before 8.21.1 contains a memory exhaustion vulnerability in lib/receiver.js where the fragment guard only triggers when fragment count reaches maxFragments, allowing attackers to exhaust memory by sending incomplete fragmented WebSocket messages. Attackers can send a text frame with FIN=0 followed by continuation frames without completing the sequence, causing each fragment to be stored as a separate Buffer object with significant overhead, enabling denial of service through heap exhaustion.

Fix

Allocation of Resources Without Limits

Weakness Enumeration

CWE-770

Related Identifiers

CVE-2026-62389

Affected Products

Ws

References · 5

• https://github.com/websockets/ws/commit/f197ac65140920bdcecdab74bfc69c2d7858e55d · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-62389 · Security Note
• https://github.com/websockets/ws/releases/tag/8.21.1 · Note
• https://github.com/websockets/ws/issues/2331 · Note
• https://vulncheck.com/advisories/ws-default-maxfragments-allows-memory-exhaustion-dos · Note