CVE-2025-68817
A critical use‑after‑free bug in the Linux kernel’s SMB server (ksmbd) can let an attacker crash the system or potentially execute code. The flaw occurs when many connections are opened and closed at the same time, freeing a connection object while another still uses it.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel, especially version 6.6 and earlier, used in many servers and embedded devices.
Real-world impact
An attacker could cause the kernel to crash, leading to denial of service, or could potentially run arbitrary code if the use‑after‑free is exploited, compromising confidentiality, integrity, and availability of the affected system.
Why this severity
The CVSS score of 9.8 reflects that the vulnerability requires no authentication, no user interaction, and can fully compromise confidentiality, integrity, and availability. The low attack complexity and high impact make it critical.
What to do about it
- 01Update the Linux kernel to a version that includes the ksmbd use‑after‑free fix.
- 02Verify the kernel version after the update.
- 03Restart services that rely on the kernel if necessary.
NVD description indicates the issue has been resolved in the Linux kernel.
Timeline
- Jan 13, 2026 · Jan 13, 2026PublishedDisclosed 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.