CVE-2026-8159
multiparty@4.2.3 and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parse…
Impact
multiparty@4.2.3 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 multiparty@4.3.0 or higher.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | multiparty | <= 4.2.3 | 4.3.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Pillarjs | Multiparty | before 4.3.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-65x3-rw7q-gx94
- https://github.com/pillarjs/multiparty/security/advisories/GHSA-65x3-rw7q-gx94
- https://nvd.nist.gov/vuln/detail/CVE-2026-8159
- https://cna.openjsf.org/security-advisories.html
- https://github.com/pillarjs/multiparty/releases/tag/v4.3.0
- https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS