CVE-2025-39933
A critical flaw in the Linux kernel’s SMB client could allow attackers to crash the client or potentially gain elevated privileges. The issue was fixed by adding verification checks in the recv_done function. Users should update to the patched kernel version to protect their systems.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel users running version 6.17 or earlier, especially those using the SMB client.
Real-world impact
An attacker could crash the SMB client, causing a denial of service, and potentially gain elevated privileges on the affected system.
Why this severity
The CVSS score of 9.4 reflects the vulnerability’s high impact on confidentiality, integrity, and availability, and the fact that it can be exploited remotely with no authentication or user interaction.
What to do about it
- 01Upgrade to Linux kernel 6.17 or later.
NVD-referenced vendor advisory
Timeline
- Oct 4, 2025 · Oct 4, 2025PublishedDisclosed and added to the National Vulnerability Database.
- Jul 30, 2026 · 6d agoAdvisory updatedThe NVD record was last revised.
- Jul 30, 2026 · 6d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.