What is CVE-2026-82333?

CVE-2026-82333 is a high-severity uncontrolled resource consumption vulnerability in multer (npm), affecting versions < 2.3.0. It is fixed in 2.3.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.

How severe is CVE-2026-82333?

CVE-2026-82333 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-2026-82333?

multer (npm) versions < 2.3.0 is affected.

Is there a fix for CVE-2026-82333?

Yes. CVE-2026-82333 is fixed in 2.3.0. Upgrade to this version or later.

Is CVE-2026-82333 exploitable, and should I be worried?

Whether CVE-2026-82333 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.

What actually determines whether CVE-2026-82333 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-2026-82333?

Upgrade multer to 2.3.0 or later.

CVE-2026-82333 in multer

Q: How severe is CVE-2026-82333?

CVE-2026-82333 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.

Q: Which versions of multer are affected by CVE-2026-82333?

multer (npm) versions < 2.3.0 is affected.

Q: Is there a fix for CVE-2026-82333?

Yes. CVE-2026-82333 is fixed in 2.3.0. Upgrade to this version or later.

Q: Is CVE-2026-82333 exploitable, and should I be worried?

Whether CVE-2026-82333 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.

Q: What actually determines whether CVE-2026-82333 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.

Q: How do I fix CVE-2026-82333?

Upgrade multer to 2.3.0 or later.

Summary

multer vulnerable to Denial of Service via oversized array index in field names

Workarounds

None.

Impact

multer is vulnerable to a Denial of Service (DoS) via a crafted array index in multipart field names. The append-field dependency parses bracket notation in field names, and a large numeric index such as items[4294967294] forces allocation of a maximum-length sparse array. A following field with a non-numeric key on the same base then converts that array to an object by iterating its full length, which consumes CPU synchronously and leaves the process unable to handle other requests. A single HTTP request with a crafted multipart body is sufficient to exploit this, and it affects multer 1.x and 2.x.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2026-82333 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 (2.3.0); upgrading removes the vulnerable code path.

Affected versions

multer (< 2.3.0)

Security releases

multer → 2.3.0 (npm)

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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Remediation advice

Users should upgrade to 2.3.0 and configure limits.fieldArrayIndexLimit to the minimum array index their application requires.

Frequently Asked Questions

What is CVE-2026-82333? CVE-2026-82333 is a high-severity uncontrolled resource consumption vulnerability in multer (npm), affecting versions < 2.3.0. It is fixed in 2.3.0. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
How severe is CVE-2026-82333? CVE-2026-82333 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-2026-82333? multer (npm) versions < 2.3.0 is affected.
Is there a fix for CVE-2026-82333? Yes. CVE-2026-82333 is fixed in 2.3.0. Upgrade to this version or later.
Is CVE-2026-82333 exploitable, and should I be worried? Whether CVE-2026-82333 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-2026-82333 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-2026-82333? Upgrade multer to 2.3.0 or later.