undici is an HTTP client library for Node.js. In versions 4.2.1 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, the client process crashes when a TLS 1.2 server renegotiates after the connection is established and presents a different, CA-trusted certificate whose hostname does not match the requested host. Node.js re-runs hostname verification on the renegotiated handshake and destroys the socket with a certificate-altname error, but undici's established-socket error handler asserted that this error code could never occur, so the peer-controlled error became an uncaught assertion that terminates the Node.js process, affecting both the HTTP/1.1 and HTTP/2 paths. A malicious or compromised HTTPS endpoint reached through undici or the global fetch() can crash the client with a single server-initiated renegotiation, taking down all in-flight requests and background work in the process, and exploitation needs no CA compromise because the attacker controls the endpoint and can present two ordinary valid certificates. Only TLS 1.2 is affected, since TLS 1.3 does not support renegotiation. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, restrict outbound connections to TLS 1.3 so renegotiation cannot occur, when the target endpoints support it.
This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 1 product from nodejs organizations running these solutions should prioritize assessment and patching.
Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2026-10-15T19:17:46.600
2026-10-19T20:41:16.643
Analyzed
ce714d77-add3-4f53-aff5-83d477b104bb
CVSSv3.1: 7.5 (HIGH)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | nodejs | undici | < 6.29.1 | Yes |
| Application | nodejs | undici | < 7.30.1 | Yes |
| Application | nodejs | undici | < 8.12.2 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For nodejs's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.