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TI-2026-69100 Aliases CVE-2026-107121GHSA-4276-jw29-xwhr

Keycloak SMTP STARTTLS downgrade exposes email credentials and messages

Priority LOW 28CWE-319Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-319.

Summary

Keycloak's SMTP email configuration does not strictly enforce an encrypted connection when STARTTLS is enabled. If the encryption request is tampered with, Keycloak falls back to unencrypted communication. An attacker who can intercept network traffic can capture email credentials and message content in plain text. The weakness is CWE-319, and the CVSS 3.1 base score is 6.5 (Medium).

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00106 1st percentileScored 2026-11-07
Fix Fixed Red Hat: 2 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Red HatRed Hat build of Keycloak 26.6—26.6.8-2Patch availableCNA
Red HatRed Hat build of Keycloak 26.6—26.6-24Patch availableCNA
Red HatRed Hat build of Keycloak 26.6—26.6-24Patch availableCNA
Red HatRed Hat build of Keycloak 26.6.8——Not affectedCNA
Red HatRed Hat build of Keycloak 26.6.8——Not affectedCNA
Red HatRed Hat Single Sign-On 7——Not affectedCNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6.8-2 Patch available CNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-24 Patch available CNA
  • Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-24 Patch available CNA
  • Red Hat build of Keycloak 26.6.8 VendorRed Hat Affected — Fixed in — Not affected CNA
  • Red Hat build of Keycloak 26.6.8 VendorRed Hat Affected — Fixed in — Not affected CNA
  • Red Hat Single Sign-On 7 VendorRed Hat Affected — Fixed in — Not affected CNA

CPE names CNA · 2

CPEVersionsRoleVendor
cpe:/a:redhat:build_keycloak:26.6::el926.6—Red Hat
cpe:/a:redhat:red_hat_single_sign_on:77—Red Hat
  • cpe:/a:redhat:build_keycloak:26.6::el9 Versions 26.6 — ·Red Hat
  • cpe:/a:redhat:red_hat_single_sign_on:7 Versions 7 — ·Red Hat

Remediation

Update Red Hat build of Keycloak 26.6 to 26.6.8-2 or 26.6-24, as described in RHSA-2026:95762 and RHSA-2026:95761, both released 2026-11-06. Red Hat build of Keycloak 26.6.8 and Red Hat Single Sign-On 7 are listed as not affected.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Red Hat 2 advisories

  • RHSA-2026:95762 Released 2026-11-06 · Red Hat rating Important
    Red Hat build of Keycloak 26.6.8 Images Security Update
    • Red Hat build of Keycloak 26.6 rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator
  • RHSA-2026:95761 Released 2026-11-06 · Red Hat rating Important
    Red Hat build of Keycloak 26.6.8 Security Update
    • Red Hat build of Keycloak 26.6.8

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat build of Keycloak 26.6Fixed RHSA-2026:95762
Red Hat build of Keycloak 26.6.8Fixed RHSA-2026:95761
Not affected: 1 product
  • Red Hat Single Sign-On 7

Timeline

  1. 2026-10-07 Threatist record created from CVE-2026-107121
  2. 2026-10-07 Alias added: GHSA-4276-jw29-xwhr
  3. 2026-10-07 Affected versions changed · Red Hat
  4. 2026-10-07 CVSS score added · Red Hat
  5. 2026-10-07 CISA SSVC decision points changed
  6. 2026-10-07 Priority changed: MEDIUM → LOW
  7. 2026-11-06 Affected versions changed · CNA
  8. 2026-11-06 1 new reference · CNA
  9. 2026-11-06 Fix available: RHSA-2026:95761 · Red Hat
  10. 2026-11-06 Fix available: Red Hat build of Keycloak 26.6.8 · Red Hat
  11. 2026-11-06 Fix available: rhbk/[email protected], rhbk/[email protected], rhbk/[email protected] · CNA
  12. 2026-11-06 1 new reference · CNA
  13. 2026-11-06 Fix available: RHSA-2026:95762 · Red Hat
  14. 2026-11-06 Fix available: Red Hat build of Keycloak 26.6 · Red Hat

References

Advisory 2

Other 2

  • TI-2019-15875 Protection mechanism failure in Jenkins Pipeline: Groovy Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-15874 Protection mechanism failure in Jenkins Script Security Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
See all 7412 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences