VULNERABILITY INTELLIGENCE

CVE-2026-12151

CVSS score7.5 HIGH
EPSS probability0.79%
CISA KEVNot currently listed
Published2026-06-17
Last modified2026-09-11
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

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 >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.

Weakness classification

  • ce714d77-add3-4f53-aff5-83d477b104bb: CWE-400
  • 0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-770

Primary references