CVE-2026-107121Keycloak-services: keycloak-services: smtp starttls plaintext credential and message downgrade
Updated under an hour ago ()
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It affects Red Hat Build of Keycloak and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
- Weakness (CWE)
- CWE-319
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- redhat
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 7, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Red Hat Red Hat Build of Keycloak redhat:build_keycloak | All versions | CNA record |
Red Hat Red Hat Single Sign-On 7 redhat:red_hat_single_sign_on | 7 | CNA record |
References
- https://access.redhat.com/security/cve/CVE-2026-107121vdb-entry, x-refsource-redhat
- https://bugzilla.redhat.com/show_bug.cgi?id=2547296issue-tracking, x-refsource-redhat
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.