CVE-2026-105482

A flaw was found in the Node.js DNS resolver APIs. Hostnames passed to dns.resolve that contain an embedded NUL character can be truncated when processed by c-ares. An attacker who can supply such a name may cause the application to resolve and act on an unintended hostname.

This issue is rated Important. Exploitation requires that the application resolve an attacker-influenced hostname containing an embedded NUL via dns.resolve (callback or promise APIs). Attack Complexity is High because the NUL-bearing name must reach those APIs and the application must rely on the returned records (for example to open a subsequent connection). Successful abuse can redirect trust in name resolution and lead to confidentiality and integrity impact comparable to connecting to the wrong host; Availability is not directly affected. Upstream rates this High and fixed it in Node.js 22.23.4, 24.22.1, and 26.12.1.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate, do not pass untrusted strings into dns.resolve; reject hostnames that contain embedded NUL bytes before DNS resolution. Limit which components may perform DNS lookups on attacker-influenced names, and restrict network reachability of those services.

--- CME Mitigation Guidance (2026-11-02) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.

The highest-value action is to reject hostnames containing embedded NUL bytes before passing them to Node.js DNS resolution APIs or underlying c-ares C strings: upgrade to Node.js 22.23.4, 24.22.1, and 26.12.1 (or the fixed Nodejs/Hi/Nodejs/Nodejs:24/Nodejs/Nodejs:22/Nodejs/Nodejs:26/Nodejs/Cloudservices/Subscription Central Automation builds), which validate resolve inputs and reject hostnames containing null bytes before passing them to c-ares, closing all 2 injection vectors (embedded NUL byte hostname truncation, domain allowlist validation bypass). Until patched, this is a concern on Applications running Node.js that resolve untrusted, attacker-influenced hostnames via dns.resolve or dns.reverse APIs, so Reject hostnames containing embedded NUL characters before calling dns.resolve or dns.reverse, and restrict which components perform DNS lookups on untrusted input. As a compensating measure, Enforce outbound network egress filtering to restrict unauthorized application connections if a truncated hostname resolves to external destinations and Implement certificate pinning to prevent establishing TLS sessions when connecting to unintended hosts that do not match expected pinned certificates. These controls limit blast radius and contain exploitation, but they do not fix the underlying embedded NUL byte hostname truncation defect — apply the upstream patch to fully remediate.

Highest-impact CME: CME-1315 Allowlist-Preferred Input Validation (Deny-by-Default Filtering) (high)