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Fencer Intel
high 8.6

CVE-2021-23342 json

Cross-site Scripting (XSS)

published 5y ago modified 4mo ago also GHSA-2mm9-c2fx-c7m4 , EUVD-2021-0585

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

This affects the package docsify before 4.12.0. It is possible to bypass the remediation done by CVE-2020-7680 and execute malicious JavaScript through the following methods 1) When parsing HTML from remote URLs, the HTML code on the main page is sanitized, but this sanitization is not taking place in the sidebar. 2) The isURL external check can be bypassed by inserting more “////” characters

Patch / fix

  • npm docsify 4.12.0
  • n/a docsify 4.12.0

Is CVE-2021-23342 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.66% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • snyk.io https://snyk.io/vuln/SNYK-JS-DOCSIFY-1066017 referenced PoC, tagged "exploit" by a source, unverified
  • snyk.io https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1076593 referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/161495/docsify-4.11.6-Cross-Site-Scripting.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:P/RL:U/RC:C
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm docsify
<4.12.0
4.12.0

Affected products

  • n/a docsify

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel 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.