How severe is CVE-2021-22540?

CVE-2021-22540 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-2021-22540 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22540?

CVE-2021-22540 affects Dart Dart Software Development Kit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22540?

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

When was CVE-2021-22540 published?

CVE-2021-22540 was published on 2021-04-22 and last updated on 2026-06-17.

CVE-2021-22540

CVE-2021-22540 is a medium-severity vulnerability in Dart Dart Software Development Kit 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% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Dart Dart Software Development Kit
Published: 2021-04-22
Last modified: 2026-06-17

Description

Bad validation logic in the Dart SDK versions prior to 2.12.3 allow an attacker to use an XSS attack via DOM clobbering. The validation logic in dart:html for creating DOM nodes from text did not sanitize properly when it came across template tags.

Frequently asked questions

What is CVE-2021-22540?: Bad validation logic in the Dart SDK versions prior to 2.12.3 allow an attacker to use an XSS attack via DOM clobbering. The validation logic in dart:html for creating DOM nodes from text did not sanitize properly when it came across template tags.
How severe is CVE-2021-22540?: CVE-2021-22540 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-2021-22540 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22540?: CVE-2021-22540 affects Dart Dart Software Development Kit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22540?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-22540 published?: CVE-2021-22540 was published on 2021-04-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:dart:dart_software_development_kit:*:*:*:*:*:*:*:*

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