# CVE-2026-104041: Sssd: sssd: denial of service via unbounded negative cache growth

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

A flaw was found in SSSD. An unprivileged local user can repeatedly request lookups for nonexistent entries through the Name Service Switch (NSS) responder. Because the negative cache does not limit the total number of stored entries and only removes expired records when an existing key is rechecked, the cache can grow without bound. This behavior can lead to memory exhaustion, resulting in a Denial of Service (DoS) as the responder becomes unresponsive or terminates.

## Remediation

- workaround: Set `entry_negative_timeout = 0` in the `[nss]` section of `/etc/sssd/sssd.conf` to disable non-permanent negative-cache insertions, then restart the SSSD service (for example, `systemctl restart sssd`) to apply the change. Note that restarting sssd briefly interrupts active authentication and identity lookups, and disabling the negative cache increases lookup traffic to identity backends for nonexistent entries. If responder memory growth is observed, the accumulated negative-cache state can be cleared through the existing operational clear path or by restarting the responder. Restricting untrusted local users also limits exposure on systems where the NSS responder socket is reachable by local users. (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: 0.14% as of 2026-11-05; percentile 3.13%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-770

## Exploit evidence

- exploit: https://bugzilla.redhat.com/show_bug.cgi?id=2478864 (ADP: CISA-ADP)

## References

- https://access.redhat.com/security/cve/CVE-2026-104041 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2478864 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2478864 (ADP: CISA-ADP; exploit)

- https://access.redhat.com/security/cve/CVE-2026-104041 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2478864 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2478864 (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-104041; retrieved 2026-11-05; source updated 2026-11-05

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104041; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-104041; retrieved 2026-11-05; source updated Not reported

Revision: 6b5ad6cb0c74fad316257651ff5ff6a6a3d22323875918c71c67bed9c17c8ca1

Canonical: https://y2.dev/cve/CVE-2026-104041

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