How severe is CVE-2020-26870?

CVE-2020-26870 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-2020-26870 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26870?

CVE-2020-26870 primarily affects Cure53 Dompurify. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-26870?

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

When was CVE-2020-26870 published?

CVE-2020-26870 was published on 2020-10-07 and last updated on 2026-06-17.

CVE-2020-26870

CVE-2020-26870 is a medium-severity vulnerability in Cure53 Dompurify 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: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Cure53 Dompurify
Published: 2020-10-07
Last modified: 2026-06-17

Description

Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.

Frequently asked questions

What is CVE-2020-26870?: Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.
How severe is CVE-2020-26870?: CVE-2020-26870 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-2020-26870 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26870?: CVE-2020-26870 primarily affects Cure53 Dompurify. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-26870?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-26870 published?: CVE-2020-26870 was published on 2020-10-07 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:cure53:dompurify:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2017:15.9:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2019:16.0:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2019:16.4:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2019:16.7:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:visual_studio_2019:16.8:*:*:*:*:*:*:*
cpe:2.3:a:oracle:application_express:*:*:*:*:*:*:*:*

More vulnerabilities in Cure53 Dompurify

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