Insecure Defaults Allow MITM Over TLS in engine.io-client
Affected versions of engine.io-client do not verify certificates by default, and as such may be vulnerable to Man-in-the-Middle attacks.
The vulnerability is related to the way that node.js handles the rejectUnauthorized setting. If the value is something that evaluates to false, such as undefined or null, certificate verification will be disabled.
Recommendation
Update to version 1.6.9 or later.
If you are unable to upgrade, ensure all calls to socket.io to have a rejectedUnauthorized: true flag.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | engine.io-client | < 1.6.9 | 1.6.9 |
References
- CVSS vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-300- Platform
- npm
- Package
engine.io-client- Disclosed
- 18.02.2019
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-4r4m-hjwj-43p8 - CC BY 4.0
Vulnerability history: engine.io-client
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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