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Fencer Vulns
medium 6.3

CVE-2021-21384 json

Null characters not escaped in shescape

published 2021-03-18 5 y ago modified 2026-09-10 1 mo ago also GHSA-f2rp-38vg-j3gh , EUVD-2021-0648

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

shescape is a simple shell escape package for JavaScript. In shescape before version 1.1.3, anyone using _Shescape_ to defend against shell injection may still be vulnerable against shell injection if the attacker manages to insert a into the payload. For an example see the referenced GitHub Security Advisory. The problem has been patched in version 1.1.3. No further changes are required.

Patch / fix

  • npm shescape 1.1.3
  • shescape_project shescape 1.1.3

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ericcornelissen/shescape/security/advisories/GHSA-f2rp-38vg-j3gh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm shescape
<1.1.3
1.1.3

Affected products

  • ericcornelissen shescape

Classification

Weakness
  • CWE-88 Improper Neutralization of Argument Delimiters in a Command

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.