CVE-2026-52944 Linux CVE debrief

Who should care

Linux administrators and users with shared filesystems, particularly those using kernel versions 5.15 through 7.0.12, should assess exposure and apply patches to prevent unauthorized file attribute modifications.

Why it matters

The vulnerability in the Linux kernel's ksmbd module allows clients to bypass FSCTL permissions, potentially enabling unauthorized modification of file attributes on shared filesystems. Linux administrators and users with shared filesystems should assess exposure and apply patches to prevent unauthorized file attribute modifications.

• Verify and apply patches for Linux kernel versions 5.15 through 7.0.12
• Assess exposure based on specific deployment contexts and shared filesystem configurations
• Review file system access controls and user permissions

Technical summary

The Linux kernel's ksmbd module did not properly check permissions for the FSCTL_SET_SPARSE operation, allowing clients to modify file sparse attributes without proper authorization. This issue has been addressed with patches available for various kernel versions, including Linux kernel versions 5.15 through 7.0.12. The vulnerability enables unauthorized modification of file attributes on shared filesystems, potentially leading to security breaches if exploited. Defenders should apply patches and review file system access controls to mitigate the vulnerability.

Defensive priority

Apply patches to address the vulnerability, particularly for Linux kernel versions 5.15 through 7.0.12, and assess exposure based on specific deployment contexts.

Recommended defensive actions

• Apply patches to address the vulnerability, particularly for Linux kernel versions 5.15 through 7.0.12
• Assess exposure based on specific deployment contexts and shared filesystem configurations
• Verify file system configurations and access controls
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected kernel versions. Multiple patch references are available, including official advisories from Linux kernel maintainers and detailed vulnerability assessments from NIST. The vulnerability has been resolved with patches available for various kernel versions. Defenders should verify affected systems, review file system access controls, and apply patches to address the vulnerability.

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.