CVE-2026-104041

Sssd: sssd: denial of service via unbounded negative cache growth

Published Oct 6, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
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

Vendor 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.

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:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:5
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Sssd
Sssd sssd
Vendors & Products Sssd
Sssd sssd
Type Values Removed Values Added
Description 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.
Title Sssd: sssd: denial of service via unbounded negative cache growth
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-770
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': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/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, 5:24 PM
Status
Undergoing Analysis
Published
Oct 6, 2026, 2:17 AM
Modified
Nov 5, 2026, 4:17 PM
Severity
Moderate
Public date
Oct 6, 2026, 12:42 AM