CVE-2026-12590

body-parser vulnerable to denial of service when invalid limit value silently disables size enforcement

Workarounds

Validate limit before passing it to body-parser. For example, parse the value with bytes.parse() at startup and reject any configuration where it returns null or a non-finite number.

References

• #698: fix PR
• bytes.js: limit parser

When body-parser is configured with an invalid limit option value, such as an unparseable string or NaN, bytes.parse() returns null and the request body size check is silently skipped. Applications that rely on limit as their primary safeguard against oversized request bodies will accept arbitrarily large payloads, leading to excessive memory and CPU usage and denial of service.

This issue affects applications that pass a programmatically computed or user-configurable value to the limit option without validating it first.

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-2026-12590 has a CVSS score of 3.7 (Low). 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 (1.20.6, 2.3.0); upgrading removes the vulnerable code path.

Kodem intelligence

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This issue is fixed in [email protected] and [email protected] via #698. After the fix, invalid limit values throw a clear error at parser construction time instead of silently disabling enforcement. null and undefined continue to fall back to the default limit (100kb).

1. What is CVE-2026-12590? CVE-2026-12590 is a low-severity allocation of resources without limits or throttling vulnerability in body-parser (npm), affecting versions < 1.20.6. It is fixed in 1.20.6, 2.3.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is CVE-2026-12590? CVE-2026-12590 has a CVSS score of 3.7 (Low). 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.
3. Which versions of body-parser are affected by CVE-2026-12590? body-parser (npm) versions < 1.20.6 is affected.
4. Is there a fix for CVE-2026-12590? Yes. CVE-2026-12590 is fixed in 1.20.6, 2.3.0. Upgrade to this version or later.
5. Is CVE-2026-12590 exploitable, and should I be worried? Whether CVE-2026-12590 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
6. What actually determines whether CVE-2026-12590 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.
7. How do I fix CVE-2026-12590?
   • Upgrade body-parser to 1.20.6 or later
   • Upgrade body-parser to 2.3.0 or later

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