# CVE-2026-104035: Sssd: sssd: denial of service via memory exhaustion in kcm responder

Status: published. Published: 2026-10-06. Updated: 2026-11-05.

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.

## Remediation

- 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: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (sssd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (sssd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (sssd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (sssd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (sssd): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.10% as of 2026-11-05; percentile 0.65%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-772

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-104035 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2479107 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-104035 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2479107 (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-104035; retrieved 2026-11-05; source updated 2026-11-05

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104035; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-104035; retrieved 2026-11-05; source updated Not reported

Revision: 36e93427078d377a7e8625253fec1af5186684ccb4f159b1d7e9b0704f6cbb64

Canonical: https://y2.dev/cve/CVE-2026-104035

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