Description
[email protected] and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parser. A crafted multipart upload with a long header value can cause regex matching to take seconds, blocking the event loop. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: limiting upload sizes at the proxy or gateway layer reduces but does not eliminate the attack surface, since a small header of around 8 KB is sufficient to trigger the vulnerable backtracking. Upgrade to [email protected] or higher.
Affected products
pillarjs: multiparty
References3
- github.com/pillarjs/multiparty/security/advisories/GHSA-65x3-rw… MitigationVendor Advisory
- cna.openjsf.org/security-advisories.html Third Party Advisory
- owasp.org/www-community/attacks/Regular_expression_Denial_of_Se… Not Applicable
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 27 · as of 14 November 2026
- CWE
- CWE-1333
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.