TLS trust bypass via undefined rejection option
Published Aug 16, 2021 · Updated Apr 30, 2025
Improper certificate validation in affected Node.js releases allows man-in-the-middle attackers to bypass TLS server trust checks. In lib/_tls_wrap.js, a truthiness test treats an explicitly undefined rejectUnauthorized option as false, so onConnectSecure retains a connection after certificate verification fails. The application must pass that undefined option and the attacker must control the TLS peer or network path; accepted traffic can then be read or modified.
Summary
What happened
Improper certificate validation in affected Node.js releases allows man-in-the-middle attackers to bypass TLS server trust checks. In lib/_tls_wrap.js, a truthiness test treats an explicitly undefined rejectUnauthorized option as false, so onConnectSecure retains a connection after certificate verification fails. The application must pass that undefined option and the attacker must control the TLS peer or network path; accepted traffic can then be read or modified.
The record
- CVE
- CVE-2021-22939
- Published
- Aug 16, 2021
- Updated
- Apr 30, 2025
- Vendor
- Node.js
- Product
- Node.js
- Classifications
- CWE-295, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 16, 2021CVE publishedPublication date reported by the CVE source.
- Apr 30, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0 <10.*
- Affected versionversion=11.0 <11.*
- Affected versionversion=12.0 <12.22.5
- Affected versionversion=13.0 <13.*
- Affected versionversion=14.0 <14.17.5
- Affected versionversion=15.0 <15.*
- Affected versionversion=16.0 <16.6.2
- Affected versionversion=4.0 <4.*
- Affected versionversion=5.0 <5.*
- Affected versionversion=6.0 <6.*
- Affected versionversion=7.0 <7.*
- Affected versionversion=8.0 <8.*
- Affected versionversion=9.0 <9.*
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- HTTPS certificate non-validation demonstrationproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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