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Fencer Vulns
medium 6.1

CVE-2021-35513 json

Cross-site Scripting in Mermaid

published 2021-06-27 5 y ago modified 2026-06-17 4 mo ago also GHSA-4f6x-49g2-99fm , EUVD-2021-2437

cvss
6.1
version 3.1, NVD
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

Mermaid before 8.11.0 allows XSS when the antiscript feature is used.

Patch / fix

  • npm mermaid 8.11.0
  • mermaid_project mermaid 8.11.0
  • node-mermaid Debian 14 8.7.0+ds+~cs27.17.17-3

debian advisories DEBIAN-CVE-2021-35513

Exploit prediction

1.02% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
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 mermaid
<8.11.0
8.11.0

Classification

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

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.