6.5
Medium
CVE-2026-107121 Keycloak-services: keycloak-services: smtp starttls plaintext credential and message downgrade
Description
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.
CVSS 3.1 detail
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:NExploitable remotely over the network, without an account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- Interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Red Hat Build of Keycloak | Versions not published | |
| Red Hat Single Sign-On 7 | Versions not published | |
| Red Hat build of Keycloak 26.6.8 | Versions not published | |
| Red Hat build of Keycloak 26.6 26.6 | earliest → < 26.6-24 | 26.6-24 |
Other CVEs of Red Hat Build of Keycloak
The 277 CVEs of Red Hat Build of Keycloak →
CVE-2026-120984
Keycloak-services: keycloak-services: manage-clients to arbitrary code execution through inline javascript policy import
9.1
Critical
CVE-2026-9797
Keycloak: keycloak: privilege escalation via client authentication manipulation by an authenticated administrator
6.5
Medium
CVE-2026-97848
Keycloak-services: keycloak-services: protocol mapper with jsontype=json bypasses token sanitization
6.5
Medium
CVE-2026-97367
Keycloak-services: keycloak-services: dcr azp and sid claim substitution allows account rest session takeover
6.4
Medium