CVE-2026-123877 Node.js is vulnerable to a certificate validation bypass in https.Agent via cross-policy TLS session reuse
Node.js apps using https.Agent may send TLS data to a server whose policy rejects it, because session reuse skips stricter CA checks.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- Yes
- Fix
- Available
What is CVE-2026-123877?
CVE-2026-123877 is a medium-severity security feature bypass vulnerability in nodejs node, published on 11 Nov 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-295
Which versions are affected by CVE-2026-123877?
An affected version is only exploitable if your software calls https.Agent.prototype.getName(). Many projects that include it are not exposed.
How do I fix CVE-2026-123877?
No fix published yet.
Upgrade to the fixed version, and do not rely on a single control for protection. More about Security feature bypass.
Is CVE-2026-123877 being exploited?
There is no known exploitation of CVE-2026-123877 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-123877, BELL-CVE-2026-123877, DEBIAN-CVE-2026-123877, GHSA-4g6g-xjc7-fh73, UBUNTU-CVE-2026-123877.