CVE-2026-104036 Sssd: sssd: denial of service via out-of-bounds write in nfs idmap plugin

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.

Exploitable with local access to the machine, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Local

Attack complexity

High

Privileges required

Low

Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

High

Affected products and versions