How severe is CVE-2021-35513?

CVE-2021-35513 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-35513 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-35513?

CVE-2021-35513 affects Mermaid Project Mermaid. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-35513?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-35513 published?

CVE-2021-35513 was published on 2021-06-27 and last updated on 2026-06-17.

CVE-2021-35513

CVE-2021-35513 is a medium-severity vulnerability in Mermaid Project Mermaid with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mermaid Project Mermaid
Published: 2021-06-27
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-35513?: Mermaid before 8.11.0 allows XSS when the antiscript feature is used.
How severe is CVE-2021-35513?: CVE-2021-35513 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-35513 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35513?: CVE-2021-35513 affects Mermaid Project Mermaid. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35513?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-35513 published?: CVE-2021-35513 was published on 2021-06-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mermaid_project:mermaid:*:*:*:*:*:node.js:*:*

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