What’s Vulnerable › Vulnerabilities
CVE-2019-20866
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.9% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-06-19 · updated 2026-06-17
- Weakness: CWE-444
Description
An issue was discovered in Mattermost Server before 5.12.0. Use of a Proxy HTTP header, rather than the source address in an IP packet header, for obtaining IP address information was mishandled.
Affected products
- Mattermost: before 5.12.0 — fixed in 5.12.0
How to fix
Upgrade to a fixed version: Mattermost 5.12.0. Check the vendor advisory for mitigations.
References
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