CVE-2026-104036 Red Hat CVE debrief

Who should care

Defenders responsible for systems using SSSD's NFS idmap plugin, particularly those with exposure to local attackers, should assess their exposure and prioritize patching vulnerable systems. This includes system administrators, security teams, and IT personnel managing identity and access management services. They should review system logs, conduct inventory checks, and implement compensating controls as necessary.

Why it matters

Defenders should prioritize patching vulnerable systems, particularly those with exposure to local attackers, as this flaw can lead to a denial of service and potential memory corruption.

• Denial of Service (DoS) via service crash
• Potential corruption of adjacent process memory

Technical summary

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. The vulnerability is specific to the NFS idmap plugin and does not affect other components of SSSD.

Defensive priority

Defenders should prioritize patching vulnerable systems, particularly those with exposure to local attackers. Inventory checks and compensating controls may be necessary until patches are applied.

Recommended defensive actions

• Patch vulnerable systems, particularly those with exposure to local attackers
• Conduct inventory checks to identify potentially affected systems
• Implement compensating controls to mitigate potential impact
• Review and update incident response plans to account for potential Denial of Service (DoS) scenarios
• Monitor system logs for unusual activity related to identity mapping services
• Consider temporarily disabling affected services until patches are applied
• Track exceptions and retest remediated assets to ensure effectiveness of patches

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description and potential impact. However, specific version information and remediation steps are not provided. Defenders should verify the affected systems and review the official advisory for further guidance. The vulnerability is in the NFS idmap plugin of SSSD, which is used for identity mapping.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.