What’s Vulnerable › Vulnerabilities

CVE-2023-3581: WebSockets accept connections from HTTPS origin

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-07-17 · updated 2026-06-17
• Weakness: CWE-346

Description

Mattermost fails to properly validate the origin of a websocket connection allowing a MITM attacker on Mattermost to access the websocket APIs.

Affected products

• Mattermost: from 7.8.0 before 7.8.7; from 7.9.0 before 7.9.5; from 7.10.0 before 7.10.3 — fixed in 7.10.3, 7.8.7, 7.9.5

How to fix

Upgrade to a fixed version: Mattermost 7.10.3, 7.8.7, 7.9.5. Check the vendor advisory for mitigations.

References

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

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