CVE-2026-104034

Sssd: sssd: denial of service via use-after-free in kcm ticket renewal

Published Oct 6, 2026 CVSS 3.1 · 4.7 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in SSSD. A use-after-free vulnerability exists in the Kerberos Credential Manager (KCM) responder during Kerberos ticket-granting ticket (TGT) renewal, where a deferred callback accesses memory that has already been released. An authenticated local user with a renewable Kerberos ticket can trigger this issue on systems configured with KCM renewal, causing the KCM responder service to crash and resulting in a Denial of Service (DoS).

Remediation

Vendor Workaround

KCM ticket renewal, the affected feature, is disabled by default (tgt_renewal defaults to false). On systems where it has been enabled, it can be disabled to avoid the vulnerable code path: 1. Edit /etc/sssd/sssd.conf and set `tgt_renewal = false` in the `[kcm]` section. 2. Restart the SSSD KCM responder to apply the change: systemctl restart sssd-kcm.service Note: disabling TGT renewal means renewable Kerberos tickets stored in the KCM credential cache are no longer renewed automatically and must be re-acquired (for example, with kinit) before they expire. Restarting sssd-kcm.service briefly interrupts in-flight KCM requests.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Redhat rhel Els
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
cpe:/a:redhat:openshift:5
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
First Time appeared Redhat openshift Container Platform
Sssd
Sssd sssd
Vendors & Products Redhat openshift Container Platform
Sssd
Sssd sssd
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in SSSD. A use-after-free vulnerability exists in the Kerberos Credential Manager (KCM) responder during Kerberos ticket-granting ticket (TGT) renewal, where a deferred callback accesses memory that has already been released. An authenticated local user with a renewable Kerberos ticket can trigger this issue on systems configured with KCM renewal, causing the KCM responder service to crash and resulting in a Denial of Service (DoS).
Title Sssd: sssd: denial of service via use-after-free in kcm ticket renewal
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-825
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 3:52 PM
Reserved
Oct 1, 2026, 5:21 PM
Status
Undergoing Analysis
Published
Oct 6, 2026, 1:16 AM
Modified
Nov 5, 2026, 4:17 PM
Severity
Moderate
Public date
Oct 5, 2026, 11:29 PM