CVE-2025-10148

CVE-2025-10148 · predictable WebSocket mask

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

curl's WebSocket code did not update the 32-bit mask pattern for each new outgoing frame as the specification says. Instead it used a fixed mask that persisted and was used throughout the entire connection. A predictable mask pattern allows for a malicious server to induce traffic between the two communicating parties that could be interpreted by an involved proxy (configured or transparent) as genuine, real, HTTP traffic with content and thereby poison its cache. That cached poisoned content could then be served to all users of that proxy.

CVSS 5.3 · Medium · EPSS 0.5% · Fix available

Published

2025-09-12T05:10:37.469Z

Updated

2026-09-15T06:02:23.283Z

Stack: system

Check your server →