multiparty vulnerable to ReDoS via filename parsing
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 multipart upload with a long header value containing !filename="1 repeated can cause regex matching to take seconds, blocking the event loop. Any service accepting multipart uploads via multiparty is affected.
Patches
Users should upgrade to multiparty@4.3.0 or higher.
Workarounds
None. Limiting upload sizes at the proxy/gateway layer reduces but does not eliminate the attack surface, since a small ~8 KB header is sufficient to trigger the vulnerable backtracking.
Resources
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | multiparty | < 4.3.0 | 4.3.0 |
References
- 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
- https://github.com/pillarjs/multiparty/releases/tag/v4.3.0
- https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1333- Platform
- npm
- Package
multiparty- Disclosed
- 18.05.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-65x3-rw7q-gx94 - CC BY 4.0
Vulnerability history: multiparty
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 05.2026 05.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 3
Disclosures per year
- 2026: 3
-
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