p PatchFirst

CVE-2026-59725

CVE-2026-59725 · Socket.IO: Engine.IO Polling Transport Connection Exhaustion

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.

CVSS 7.5 · High · EPSS 0.6% · Fix available

Published
Updated

Stack: node

Affected products and versions

  • engine.io

    Versions
    • >= 4.1.0, < 6.6.7: Affected

    No fix published

  • engine.io npm

    Affected ranges
    • SEMVER: ≥ 4.1.0, < 6.6.7

    Update to 6.6.7

Original sources

Check your server →