Vulnerability in Red Hat Build Of Keycloak

CVE-2026-107121

A flaw was found in the SMTP email configuration handling of the keycloak-services component. When the STARTTLS option is enabled, Keycloak fails to strictly enforce an encrypted connection, allowing it to fall back to unencrypted communication if the encryption request is tampered with. An attacker who can intercept network traffic can exploit this to capture sensitive email credentials and message content in plain text.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-107121?
CVE-2026-107121 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Cleartext Transmission of Sensitive Information. CVSS score: 6.5/10. Published 2026-10-07.
How severe is CVE-2026-107121?
Medium severity. CVSS v3 base score is 6.5 out of 10.