CVE-2026-2581 is a medium-severity allocation of resources without limits or throttling vulnerability in undici (npm), affecting versions >= 7.17.0, < 7.24.0. It is fixed in 7.24.0.
Impact This is an uncontrolled resource consumption vulnerability (CWE-400) that can lead to Denial of Service (DoS). In vulnerable Undici versions, when interceptors.deduplicate() is enabled, response data for deduplicated requests could be accumulated in memory for downstream handlers. An attacker-controlled or untrusted upstream endpoint can exploit this with large/chunked responses and concurrent identical requests, causing high memory usage and potential OOM process termination. Impacted users are applications that use Undici’s deduplication interceptor against endpoints that may produce large or long-lived response bodies. Patches The issue has been patched by changing deduplication behavior to stream response chunks to downstream handlers as they arrive (instead of full-body accumulation), and by preventing late deduplication when body streaming has already started. Users should upgrade to the first official Undici (and Node.js, where applicable) releases that include this patch. Workarounds If upgrading immediately is not possible: Disable interceptors.deduplicate() for affected clients/routes. Use skipHeaderNames with a marker header to force high-risk requests to bypass deduplication. Avoid concurrent identical requests to untrusted endpoints that may return very large/chunked bodies. Apply upstream/proxy response-size and timeout limits.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
CVE-2026-2581 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (7.24.0). Upgrading removes the vulnerable code path.
npm
undici (>= 7.17.0, < 7.24.0)undici → 7.24.0 (npm)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-2581 is reachable in your applications. Explore open-source security for your team.
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Upgrade undici to 7.24.0 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-2581 is a medium-severity allocation of resources without limits or throttling vulnerability in undici (npm), affecting versions >= 7.17.0, < 7.24.0. It is fixed in 7.24.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
CVE-2026-2581 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
undici (npm) versions >= 7.17.0, < 7.24.0 is affected.
Yes. CVE-2026-2581 is fixed in 7.24.0. Upgrade to this version or later.
Whether CVE-2026-2581 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade undici to 7.24.0 or later.