Sssd: sssd: denial of service via use-after-free in kcm ticket renewal
Summary
| CVE | CVE-2026-104034 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-06 01:16:34 UTC |
| Updated | 2026-11-05 16:17:25 UTC |
| 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). |
Risk And Classification
Primary CVSS: v3.1 4.7 MEDIUM from [email protected]
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000890000 probability, percentile 0.003830000 (date 2026-11-05)
Problem Types: CWE-825 | CWE-825 Expired Pointer Dereference
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 4.7 | MEDIUM | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 4.7 | MEDIUM | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 5 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-104034 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: This issue was discovered by Found by AISLE in partnership with Red Hat. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-05-18T03:32:25.000Z | Reported to Red Hat. |
| CNA | 2026-10-05T23:29:37.004Z | Made public. |
Workarounds
CNA: 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.