Vulnerability library
Security checkSeptember 29, 2026

Socket.IO: Engine.IO Protocol Revision Mismatch DoS

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High severitynpmengine.io

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Description

A denial-of-service vulnerability exists in Engine.IO / Socket.IO servers that allow transport upgrades.

The Engine.

Recommendation

Update the engine.io package to the latest compatible version. Followings are version details:

  • Affected version(s): >= 6.6.0, < 6.6.10
  • Patched version(s): 6.6.10

References

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See something that needs correcting? Let us knowUpdated September 29, 2026