7.5

CVE-2026-8159: multiparty

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-8159DEBIAN-CVE-2026-8159GHSA-65x3-rw7q-gx94
Published 12-05-2026Last modified 12-05-2026
Open JSON

Vulnerability summary

CVE-2026-8159 is a high (CVSS 7.5) vulnerability in multiparty. EPSS estimates a 0.62% chance of exploitation in the next 30 days, higher than 48.8% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.62%
0%100%
Low · +0.28 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 12-05-2026
    PublishedVulnerability first disclosed.
  2. 12-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.62%

Chance of exploitation in the next 30 days

Percentile

49%

Versus all other CVEs

30-day change

+0.28 pp

From 0.34% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.62%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • node-multipartyAll versions (No fix recorded) | < 4.3.0-1
Multiparty1 product
Npm1 product
  • multiparty< 4.3.0
Pillarjs1 product
Ubuntu1 product
  • node-multipartyAll versions (No fix recorded)

5 vendors · 5 products

References

9 links