CVE-2026-107121
Keycloak-services: keycloak-services: smtp starttls plaintext credential and message downgrade
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-319 |
| Vendor | red hat |
| Product | red hat build of keycloak |
| Published | Oct 7, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None
Affected Versions
Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Build of Keycloak
All versions affected Red Hat / Red Hat Single Sign-On 7
All versions affected References
Credits
Red Hat would like to thank Paul Bottinelli of Trail of Bits in collaboration with OpenAI for reporting this issue.