Linux · Kernel
CVE-2021-22600
Double Free in net/packet/af_packet.c leading to priviledge escalation
What it is
A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755
CISA: Linux Kernel contains a flaw in the packet socket (AF_PACKET) implementation which could lead to incorrectly freeing memory. A local user could exploit this for denial-of-service (DoS) or possibly for privilege escalation.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 2, 2022
More exploited flaws from Linux
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 18, 2026 | Improper Check for Unusual or Exceptional Conditions | Kernel | Critical 9.8 | 3.3% |
| Sep 18, 2026 | Race Condition | Kernel | High 7.8 | 1.6% |
| Sep 18, 2026 | Out-of-Bounds Write | Kernel | High 8.8 | 0.9% |
| Aug 27, 2026 | Unspecified | Kernel | High 7.8 | 0.7% |
| Aug 26, 2026 | Out-of-Bounds Write | Kernel | High 7.8 | 8.9% |
| Jun 2, 2026 | Improper Authentication | Kernel | High 7.8 | 5.5% |
| May 1, 2026 | Incorrect Resource Transfer Between Spheres | Kernel | High 7.8 | 98% |
| Jan 26, 2026 | Integer Overflow | Kernel | High 7.8 | 15% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.