Summary
multer vulnerable to Denial of Service via a pending asynchronous fileFilter after request teardown
Workarounds
Use a synchronous fileFilter.
Impact
When multer is configured with an asynchronous fileFilter, a single request can crash the Node.js process. If a request is aborted (for example when one file is rejected) while another file's async fileFilter is still pending, the pending callback later resumes a parsing stream that multer has already torn down. busboy then emits an error on a stream that no longer has an error listener, which Node raises as an unhandled 'error' event, and the process exits. A single unauthenticated request is enough, so any application using multer with an asynchronous fileFilter is affected, regardless of storage engine. Uploads using a synchronous fileFilter are not affected.
CVE-2026-113872 has a CVSS score of 7.5 (High). 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 (2.5.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Users should upgrade to multer 2.5.0 or later.
Frequently Asked Questions
- What is CVE-2026-113872? CVE-2026-113872 is a high-severity security vulnerability in multer (npm), affecting versions >= 2.0.0, < 2.5.0. It is fixed in 2.5.0.
- How severe is CVE-2026-113872? CVE-2026-113872 has a CVSS score of 7.5 (High). 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.
- Which versions of multer are affected by CVE-2026-113872? multer (npm) versions >= 2.0.0, < 2.5.0 is affected.
- Is there a fix for CVE-2026-113872? Yes. CVE-2026-113872 is fixed in 2.5.0. Upgrade to this version or later.
- Is CVE-2026-113872 exploitable, and should I be worried? Whether CVE-2026-113872 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
- What actually determines whether CVE-2026-113872 is exploitable, and how bad it is? 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.
- How do I fix CVE-2026-113872? Upgrade
multerto 2.5.0 or later.