CVE-2026-8159: multiparty · ReDoS
Affects multipartySource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 4.3.0 : patch multiparty soon.
Data as of 11 Nov 2026, 23:07 UTC
Thin evidence
One scorer or none| CNA (openjs) | CVSS 3.1 | 7.5 |
|---|
- Patch
- Available – fixed in 4.3.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| multiparty multiparty | Affected
| Fixed in– |
AI-suggested
Upgrade multiparty to version 4.3.0 or higher to fully remediate this vulnerability. Limiting upload sizes at proxy or gateway layers can reduce the attack surface but does not fully prevent exploitation due to the low threshold (~8 KB) required to trigger the issue.
Description
multiparty versions up to 4.2.3 have a denial of service vulnerability caused by inefficient regular expression processing in the Content-Disposition filename parameter parser. A crafted multipart upload with a long header value can trigger excessive regex backtracking, blocking the event loop and causing service disruption. This affects any service using multiparty for multipart uploads. Upgrading to multiparty version 4.3.0 or later resolves the issue.