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Fencer Vulns
medium 6.5

CVE-2021-23771 json

Sandbox Bypass

published 2022-03-17 4 y ago modified 2026-06-17 4 mo ago also GHSA-8g4m-cjm2-96wq , EUVD-2022-1375

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

This affects all versions of package notevil; all versions of package argencoders-notevil. It is vulnerable to Sandbox Escape leading to Prototype pollution. The package fails to restrict access to the main context, allowing an attacker to add or modify an object's prototype. **Note:** This vulnerability derives from an incomplete fix in [SNYK-JS-NOTEVIL-608878](https://security.snyk.io/vuln/SNYK-JS-NOTEVIL-608878).

Exploit prediction

1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-JS-NOTEVIL-2385946 referenced PoC, tagged "exploit" by a source, unverified
  • snyk.io https://snyk.io/vuln/SNYK-JS-ARGENCODERSNOTEVIL-2388587 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:P
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm notevil
<=1.3.3
 no fix listed
npm argencoders-notevil
<=2.5.0
 no fix listed

Affected products

  • n/a notevil
  • n/a argencoders-notevil

Classification

Weakness
  • CWE-1321 Improperly Controlled Modification of Object Prototype 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.