CVE-2026-12590: body-parser vulnerable to denial of service when invalid limit value silently disables size enforcement
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.
References
- cna.openjsf.org/security-advisories.html
- github.com/advisories/GHSA-v422-hmwv-36x6
- github.com/expressjs/body-parser/commit/2322e111cc321413ec2b7b76d01be533d3de9d7d
- github.com/expressjs/body-parser/commit/3492672eee593d5c158f239b6e9115498a5dbeac
- github.com/expressjs/body-parser/pull/698
- github.com/expressjs/body-parser/pull/741
- github.com/expressjs/body-parser/releases/tag/1.20.6
- github.com/expressjs/body-parser/releases/tag/v2.3.0
- github.com/expressjs/body-parser/security/advisories/GHSA-v422-hmwv-36x6
- nvd.nist.gov/vuln/detail/CVE-2026-12590
Code Behaviors & Features
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