CVE-2026-8159 json
multiparty vulnerable to ReDoS via filename parsing
published 2026-05-12 5 mo ago modified 2026-06-17 4 mo ago also GHSA-65x3-rw7q-gx94 , EUVD-2026-29439
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 26%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm multiparty 4.3.0
- multiparty multiparty 4.3.0
- node-multiparty Debian 14 4.3.0-1
debian advisories DEBIAN-CVE-2026-8159
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.34% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | multiparty | <4.3.0 |
4.3.0 |
Affected products
- multiparty multiparty
Classification
- Weakness
-
- CWE-1333 Inefficient Regular Expression Complexity
References
-
github.com
/pillarjs/multiparty/security/advisories/GHSA-65x3-rw7q-gx94
web, mitigation, vendor-advisory
-
owasp.org
/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS
web, not-applicable
-
cna.openjsf.org
/security-advisories.html
web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-8159
advisory
-
github.com
/pillarjs/multiparty
package
-
github.com
/pillarjs/multiparty/releases/tag/v4.3.0
web
Sources
- CVE List CVE-2026-8159
- GitHub Advisory GHSA-65x3-rw7q-gx94
- NVD CVE-2026-8159
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.