CVE-2026-8159
HighSummary
Versions of multiparty up to 4.2.3 are vulnerable to denial of service due to 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.
Risk Assessment
Any service accepting multipart uploads via multiparty is affected, which can lead to significant disruptions in application functionality.
Recommendation
It is recommended to upgrade to multiparty version 4.3.0 or higher to mitigate this vulnerability. Limiting upload sizes at the proxy or gateway level can reduce risk but does not eliminate it entirely.
Other vulnerabilities in multiparty
See all- CVE-2026-8162High
Versions of multiparty up to 4.2.3 are vulnerable to denial of service due to an uncaught exception. By sending a multipart/form-data request with a malformed percent-encoding in the Content-Disposition header, the parser invokes decodeURI without error handling, leading to a process crash.
- CVE-2026-8161High
Versions of multiparty up to 4.2.3 are vulnerable to denial of service due to an uncaught exception. By sending a multipart/form-data request with a field name that collides with an Object.prototype property, the parser invokes .push() on the inherited prototype value, leading to a TypeError and crashing the process.
Original NVD description (English source)
[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.