Node.js per-host mTLS auth bypass via CAonly SNI context
CVE-2026-123867 Published on November 11, 2026
Node.js is vulnerable to a per-host mTLS authorization bypass via a CA-only SNI context failing open to the default CA
A per-host mutual-TLS authorization bypass in Node.js lets a client authorized for the default hostname reach a protected hostname it is not authorized for. When a TLS server assigns a hostname a different client-certificate CA with `server.addContext(host, { ca: protectedCA })` but no server certificate in that SNI context, the per-host client CA is never installed and the handshake falls back to the default client CA. In `src/crypto/crypto_tls.cc`, `CertCbDone` installs the SNI context's CA only when `setSniContext` succeeds, but `setSniContext` returns `false` for a context with no server certificate, so a CA-only SNI context silently keeps the default CA. A client holding a certificate trusted by the default CA, but not the protected CA, can therefore complete mTLS to the protected hostname and read its response even with `requestCert` and `rejectUnauthorized` enabled, while a client certified by the protected CA is rejected. This vulnerability affects Node.js 26.x, 24.x, and 22.x.
Vulnerability Analysis
CVE-2026-123867 can be exploited with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Improper Certificate Validation
The software does not validate, or incorrectly validates, a certificate. When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.
Affected Versions
nodejs node:- Version 0.0.0 and below 22.23.5 is affected.
- Version 23.0.0 and below 24.22.3 is affected.
- Version 25.0.0 and below 26.13.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.