How severe is CVE-2021-27911?

CVE-2021-27911 has a CVSS 3.x base score of 8.3, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-27911 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27911?

CVE-2021-27911 primarily affects Acquia Mautic. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27911?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27911 published?

CVE-2021-27911 was published on 2021-08-30 and last updated on 2026-06-17.

CVE-2021-27911

CVE-2021-27911 is a high-severity vulnerability in Acquia Mautic with a CVSS 3.x base score of 8.3. 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: High (CVSS 3.x base score 8.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Acquia Mautic
Published: 2021-08-30
Last modified: 2026-06-17

Description

Mautic versions before 3.3.4/4.0.0 are vulnerable to an inline JS XSS attack through the contact's first or last name and triggered when viewing a contact's details page then clicking on the action drop down and hovering over the Campaigns button. Contact first and last name can be populated from different sources such as UI, API, 3rd party syncing, forms, etc.

Frequently asked questions

What is CVE-2021-27911?: Mautic versions before 3.3.4/4.0.0 are vulnerable to an inline JS XSS attack through the contact's first or last name and triggered when viewing a contact's details page then clicking on the action drop down and hovering over the Campaigns button. Contact first and last name can be populated from different sources such as UI, API, 3rd party syncing, forms, etc.
How severe is CVE-2021-27911?: CVE-2021-27911 has a CVSS 3.x base score of 8.3, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-27911 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27911?: CVE-2021-27911 primarily affects Acquia Mautic. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27911?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27911 published?: CVE-2021-27911 was published on 2021-08-30 and last updated on 2026-06-17.

References

https://github.com/mautic/mautic/security/advisories/GHSA-72hm-fx78-xwhc

Affected products (4)

cpe:2.3:a:acquia:mautic:*:*:*:*:*:*:*:*
cpe:2.3:a:acquia:mautic:4.0.0:alpha1:*:*:*:*:*:*
cpe:2.3:a:acquia:mautic:4.0.0:beta:*:*:*:*:*:*
cpe:2.3:a:acquia:mautic:4.0.0:rc:*:*:*:*:*:*

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