CVE-2021-47215
A critical flaw in the Linux kernel’s mlx5e driver can cause a crash when handling TLS receive resynchronization. The bug was fixed in a kernel update that protects TLS context entries during resync handling. Users running affected kernel versions should update to a patched release.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel, including version 5.16 and earlier releases that contain the mlx5e driver.
Real-world impact
An attacker could trigger the crash by sending crafted TLS traffic, leading to a denial‑of‑service on the affected system.
Why this severity
The CVSS score of 9.8 reflects that the vulnerability requires no authentication or user interaction, yet it can completely compromise confidentiality, integrity, and availability by crashing the kernel.
What to do about it
- 01Upgrade the Linux kernel to a version that includes the patch for CVE-2021-47215, such as 5.16 or later.
- 02Reboot the system to load the updated kernel.
NVD-referenced vendor advisory
Timeline
- Apr 10, 2024 · Apr 10, 2024PublishedDisclosed and added to the National Vulnerability Database.
- Aug 4, 2026 · 2d agoAdvisory updatedThe NVD record was last revised.
- Aug 5, 2026 · 22h agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.