CVE-2026-123877

Description

A certificate validation bypass in Node.js https.Agent lets a cached TLS session authenticated under one CA policy be reused by a later request with a stricter policy. https.Agent.prototype.getName() assigns the same Agent and session-cache key to a request that omits ca and one that explicitly supplies ca: [], because an omitted value appends nothing to the key while an empty array stringifies to an empty string. The two policies differ: omitting ca uses the default trust store, while supplying ca replaces it. Since they share a key, a TLS session authenticated under the broader default policy is handed to a new connection made under the later ca: [] policy, and TLS 1.3 session resumption carries the earlier authentication forward, so the second request reports authorized === true and transmits confidential data to a server its own CA policy would reject on a fresh connection. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

• How can I get the fixes?
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Severity score breakdown

CVSS version: CVSS v3.0

References

• MITRE
• NVD
• Launchpad
• Debian

Other references

• https://www.cve.org/CVERecord?id=CVE-2026-123877
• https://nodejs.org/en/blog/vulnerability/november-2026-security-releases#certificate-validation-bypass-in-nodejs-httpsagent-via-cross-policy-tls-session-reuse-cve-2026-123877---medium
• https://cna.openjsf.org/security-advisories.html
• https://nodejs.org/en/blog/vulnerability/november-2026-security-releases