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Fencer Vulns
high 7.5

CVE-2020-7699 json

Prototype Pollution

published 2020-07-30 6 y ago modified 2026-07-08 4 mo ago also GHSA-9wcg-jrwf-8gg7 , EUVD-2020-0608

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

This affects the package express-fileupload before 1.1.8. If the parseNested option is enabled, sending a corrupt HTTP request can lead to denial of service or arbitrary code execution.

Patch / fix

  • npm express-fileupload 1.1.9
  • n/a express-fileupload 1.1.8

Exploit prediction

4.76% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-JS-EXPRESSFILEUPLOAD-595969 referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/richardgirges/express-fileupload/issues/236 referenced PoC, tagged "exploit" by a source, unverified

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
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm express-fileupload
<1.1.9
1.1.9

Affected products

  • n/a express-fileupload

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype Attributes
  • CWE-915 Improperly Controlled Modification of Dynamically-Determined Object Attributes

References

Sources

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.