What’s Vulnerable › Vulnerabilities

CVE-2020-1758

• Severity: medium (CVSS 5.9 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: 2020-05-15 · updated 2026-06-17
• Weakness: CWE-297

Description

A flaw was found in Keycloak in versions before 10.0.0, where it does not perform the TLS hostname verification while sending emails using the SMTP server. This flaw allows an attacker to perform a man-in-the-middle (MITM) attack.

Affected products

• Keycloak: before 10.0.0 — fixed in 10.0.0
• OpenStack: 10

How to fix

Upgrade to a fixed version: Keycloak 10.0.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-1758
• https://issues.redhat.com/browse/KEYCLOAK-13285
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-1758
• https://issues.redhat.com/browse/KEYCLOAK-13285

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