CVE-2026-104035
Sssd: sssd: denial of service via memory exhaustion in kcm responder
A flaw was found in SSSD. An issue in the Kerberos Credential Manager (KCM) responder allows a local user to cause a Denial of Service (DoS) by maintaining a persistent connection and repeatedly storing and destroying credentials. Because the service fails to release cached objects from memory when credentials are removed, memory consumption grows continuously, ultimately exhausting available memory and rendering the service unresponsive.
Fixes and workarounds
Workaround
This issue can only be exploited when the SSSD KCM responder is enabled and reachable by a local user, so mitigation focuses on limiting that exposure. On systems that do not require KCM credential caching, disable the KCM responder by stopping and masking the sssd-kcm socket and service: # systemctl stop sssd-kcm.socket sssd-kcm.service # systemctl mask sssd-kcm.socket sssd-kcm.service Before disabling KCM, ensure an alternative Kerberos credential cache type (for example FILE: or KEYRING:) is configured in /etc/krb5.conf, because clients or system configurations that default to KCM: credential caches would otherwise lose Kerberos ticket management. On systems where KCM is required, restrict access to the KCM UNIX socket (/var/run/.heim_org.h5l.kcm-socket) to trusted local users where deployment policy permits. If abnormal memory growth is observed, closing the abusive client connection or restarting the sssd-kcm responder reclaims the retained connection-scoped memory; these are operational workarounds rather than a fix, and no released package fix is currently established.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat sssd
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 6 Red Hat sssd
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat sssd
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat sssd
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat sssd
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-8
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 4 Red Hat openshift/ose-rhel-coreos-9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Container Platform 5 Red Hat openshift/ose-rhel-coreos-9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.5 medium |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-104035CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2479107CNA: redhat · issue-tracking, x_refsource_REDHAT
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