How severe is CVE-2018-21265?

CVE-2018-21265 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2018-21265 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-21265?

CVE-2018-21265 affects Mattermost Mattermost Desktop. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-21265?

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

When was CVE-2018-21265 published?

CVE-2018-21265 was published on 2020-06-19 and last updated on 2026-06-17.

CVE-2018-21265

CVE-2018-21265 is a medium-severity vulnerability in Mattermost Mattermost Desktop with a CVSS 3.x base score of 5.3. 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-732.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-732
Affected product: Mattermost Mattermost Desktop
Published: 2020-06-19
Last modified: 2026-06-17

Description

An issue was discovered in Mattermost Desktop App before 4.0.0. It mishandled the Same Origin Policy for setPermissionRequestHandler (e.g., video, audio, and notifications).

Frequently asked questions

What is CVE-2018-21265?: An issue was discovered in Mattermost Desktop App before 4.0.0. It mishandled the Same Origin Policy for setPermissionRequestHandler (e.g., video, audio, and notifications).
How severe is CVE-2018-21265?: CVE-2018-21265 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2018-21265 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-21265?: CVE-2018-21265 affects Mattermost Mattermost Desktop. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-21265?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-21265 published?: CVE-2018-21265 was published on 2020-06-19 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates/

Affected products (1)

cpe:2.3:a:mattermost:mattermost_desktop:*:*:*:*:*:*:*:*

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