What’s Vulnerable › Vulnerabilities

CVE-2026-93848: Mattermost OpenID discovery endpoint request bypasses outbound connection filtering, allowing SSRF by a System Administrator

• Severity: low (CVSS 2.7 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: 2026-10-26 · updated 2026-10-26
• Weakness: CWE-918

Description

Mattermost versions 11.7.x <= 11.7.10 fail to apply outbound internal-connection filtering to the OpenID discovery endpoint request which allows a System Administrator to determine whether internal addresses and ports are reachable from the server via an unauthenticated login request that triggers the discovery fetch.. Mattermost Advisory ID: MMSA-2026-00774

Affected products

• Mattermost: from 11.7.0 through 11.7.10

References

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

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