CVE-2026-104036

Sssd: sssd: denial of service via out-of-bounds write in nfs idmap plugin

Published Oct 6, 2026 CVSS 3.1 · 5.8 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in SSSD's NFS idmap plugin. When retrieving cached user or group names, the plugin detects if an entry exceeds the destination buffer size but fails to abort before copying data. A local attacker can trigger this vulnerability by requesting identity lookups that resolve to oversized cached entries, resulting in an out-of-bounds write. This flaw primarily leads to a Denial of Service (DoS) by crashing the identity mapping service, and may also corrupt adjacent process memory.

Remediation

Vendor Workaround

Disable the vulnerable memcache lookup path of the SSSD NFS idmap plugin: in the rpc.idmapd configuration, set `memcache = false` for the SSSD plugin (or switch the translation `Method` away from `sss`), and restart the rpc.idmapd service to apply the change. This makes uid/gid name lookups bypass the vulnerable get_user_from_mc() and get_group_from_mc() code paths. Note that with memcache disabled, lookups are served through the SSSD responder instead of the in-memory cache, which may add lookup latency on systems with heavy NFS identity resolution traffic. No released package fix is currently established for this issue, so this configuration change is the recommended interim workaround until a fixed build is available.

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:/a:redhat:openshift:5
cpe:/o:redhat:rhel_els:6
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Els
Type Values Removed Values Added
First Time appeared Redhat openshift Container Platform
Sssd
Sssd sssd
Vendors & Products Redhat openshift Container Platform
Sssd
Sssd sssd
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in SSSD's NFS idmap plugin. When retrieving cached user or group names, the plugin detects if an entry exceeds the destination buffer size but fails to abort before copying data. A local attacker can trigger this vulnerability by requesting identity lookups that resolve to oversized cached entries, resulting in an out-of-bounds write. This flaw primarily leads to a Denial of Service (DoS) by crashing the identity mapping service, and may also corrupt adjacent process memory.
Title Sssd: sssd: denial of service via out-of-bounds write in nfs idmap plugin
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-787
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': 5.8, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 5, 2026, 3:52 PM
Reserved
Oct 1, 2026, 5:22 PM
Status
Undergoing Analysis
Published
Oct 6, 2026, 1:16 AM
Modified
Nov 5, 2026, 4:17 PM
Severity
Moderate
Public date
Oct 5, 2026, 11:47 PM