How severe is CVE-2021-27401?

CVE-2021-27401 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-2021-27401 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27401?

CVE-2021-27401 primarily affects Mitel Micollab. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27401?

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

When was CVE-2021-27401 published?

CVE-2021-27401 was published on 2021-08-13 and last updated on 2026-06-17.

CVE-2021-27401

CVE-2021-27401 is a medium-severity vulnerability in Mitel Micollab 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% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mitel Micollab
Published: 2021-08-13
Last modified: 2026-06-17

Description

The Join Meeting page of Mitel MiCollab Web Client before 9.2 FP2 could allow an attacker to access (view and modify) user data by executing arbitrary code due to insufficient input validation, aka Cross-Site Scripting (XSS).

Frequently asked questions

What is CVE-2021-27401?: The Join Meeting page of Mitel MiCollab Web Client before 9.2 FP2 could allow an attacker to access (view and modify) user data by executing arbitrary code due to insufficient input validation, aka Cross-Site Scripting (XSS).
How severe is CVE-2021-27401?: CVE-2021-27401 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-2021-27401 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27401?: CVE-2021-27401 primarily affects Mitel Micollab. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27401?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27401 published?: CVE-2021-27401 was published on 2021-08-13 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mitel:micollab:*:*:*:*:*:-:*:*
cpe:2.3:a:mitel:micollab:9.2:-:*:*:*:-:*:*
cpe:2.3:a:mitel:micollab:9.2:fp1:*:*:*:-:*:*

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