# CVE-2026-12590: OpenJS body-parser denial of service via invalid limit configuration

Source: https://junglewise.ai/threats/cve-2026-12590-openjs-body-parser-denial-of-service-via-invalid-limit  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-09. Updated: 2026-07-20  
License: CC BY 4.0 with a link back

CVE-2026-12590 · Severity: low · CVSS 3.7 · Published 2026-07-09

The body-parser library, a widely used component for handling data sent to web applications, contains a flaw where certain invalid configuration settings can accidentally disable security limits. If an application uses an unvalidated or improperly calculated size limit, an attacker could send extremely large amounts of data to the server. This can exhaust the server's memory and processing power, potentially causing the application to crash or become unavailable to legitimate users.

Technologies: [OpenJS Foundation Body-Parser](https://junglewise.ai/threats/technologies/body-parser), [Body-Parser](https://junglewise.ai/threats/technologies/npm-body-parser). Vendors: [OpenJS Foundation](https://junglewise.ai/threats/vendors/openjs-foundation).

## Quick answers

**Is CVE-2026-12590 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-12590 being exploited in the wild.

**How severe is CVE-2026-12590?** Low severity, with a CVSS score of 3.7, published 9 July 2026.

**Which products and versions are affected?** OpenJS Foundation Body-Parser < 1.20.6, >= 2.0.0 < 2.3.0; Body-Parser SEMVER:introduced=0,fixed=1.20.6.

**Is there a fix for CVE-2026-12590?** Yes. Body-Parser: upgrade to 1.20.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-12590 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-12590?** Check whether you run OpenJS Foundation Body-Parser or Body-Parser at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Body-Parser: upgrade to 1.20.6 or later

## Technical details

A vulnerability exists in body-parser where providing an invalid value (such as NaN or an unparseable string) to the 'limit' option causes the underlying 'bytes.parse()' function to return null. When this occurs, the library silently skips request body size enforcement instead of throwing an error or falling back to a safe default. An attacker can exploit this by sending oversized request bodies to applications with such misconfigurations, leading to resource exhaustion (CWE-770). The issue is fixed in versions 1.20.6 and 2.3.0, which now throw an explicit error during parser construction if an invalid limit is provided.

## Affected products

- expressjs body-parser < 1.20.6, >= 2.0.0, < 2.3.0

## Identifiers

- CVE-2026-12590
- GHSA-v422-hmwv-36x6

## Timeline

- 2026-07-09: disclosed: NVD publication date
- 2026-07-20: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/Phillip9587](https://api.github.com/users/Phillip9587)
- [https://github.com/Phillip9587](https://github.com/Phillip9587)
- [https://api.github.com/users/Phillip9587/gists%7B/gist_id%7D](https://api.github.com/users/Phillip9587/gists%7B/gist_id%7D)
- [https://api.github.com/users/Phillip9587/repos](https://api.github.com/users/Phillip9587/repos)
- [https://avatars.githubusercontent.com/u/17254592?v=4](https://avatars.githubusercontent.com/u/17254592?v=4)
- [https://api.github.com/users/Phillip9587/events%7B/privacy%7D](https://api.github.com/users/Phillip9587/events%7B/privacy%7D)

## Related threats

- [Express.js body-parser denial of service via decompression stream](https://junglewise.ai/threats/cve-2026-111181-body-parser-is-body-parsing-middleware-for-node-js-and-express)
- [body-parser denial of service in URL encoding](https://junglewise.ai/threats/cve-2025-13466-body-parser-denial-of-service-in-url-encoding)
- [body-parser denial of service in URL encoding](https://junglewise.ai/threats/cve-2024-45590-body-parser-denial-of-service-in-url-encoding)