CVE-2025-71159
A critical bug in the Linux kernel’s Btrfs filesystem can cause a use‑after‑free error, potentially allowing an attacker to crash the system or gain unauthorized access. The flaw arises from a missing memory barrier when setting reference counts for delayed nodes. The issue has been fixed in recent kernel releases.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel, particularly versions 6.19 and earlier that contain the Btrfs filesystem.
Real-world impact
An attacker could crash the system or potentially execute arbitrary code by exploiting the use‑after‑free bug, leading to denial of service or privilege escalation.
Why this severity
The CVSS score of 9.8 reflects the vulnerability’s high impact (confidentiality, integrity, availability all compromised) and the fact that it can be exploited remotely without authentication or user interaction.
What to do about it
- 01Upgrade the Linux kernel to a version that includes the fix (e.g., 6.19 or later).
- 02Reboot the system to load the updated kernel.
NVD description
Timeline
- Jan 23, 2026 · Jan 23, 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.