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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-12151

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

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Status
Published
Published
Updated
Assigning organization
openjs

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

undici undici

Default version status: unaffected

  • 0 to < 6.26.0affected
  • 6.26.0unaffected
  • 7.0.0 to < 7.28.0affected
  • 7.28.0unaffected
  • 8.0.0 to < 8.5.0affected
  • 8.5.0unaffected
pkg:npm/undici

References