# CVE-2026-8159: node-multiparty: multiparty@4.2.3 and lower versions are vulnerable to denial of service via regular expression backtracking in the Co...

CVE-2026-8159 is fixed in node-multiparty on 1 platform by DEBIAN-CVE-2026-8159 (version 4.3.0-1), released May 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-8159
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0034
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 12, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | node-multiparty Debian 14 | 4.3.0-1 | [DEBIAN-CVE-2026-8159](https://patchblox.com/security/data/fix/linux/debian-cve-2026-8159.md) | May 27, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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