CVE-2021-28691

Description

Guest triggered use-after-free in Linux xen-netback A malicious or buggy network PV frontend can force Linux netback to disable the interface and terminate the receive kernel thread associated with queue 0 in response to the frontend sending a malformed packet. Such kernel thread termination will lead to a use-after-free in Linux netback when the backend is destroyed, as the kernel thread associated with queue 0 will have already exited and thus the call to kthread_stop will be performed against a stale pointer.

CVSS Metrics

• v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• v2.0•MEDIUM•Score: 4.6AV:L/AC:L/Au:N/C:P/I:P/A:P

EPSS Trends

Current EPSS score: 0.03%• Percentile: 9%

Techniques & Countermeasures

• CWE-416•Use After Free

  The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

• linux•linux

  ≥ 5.5.0, < unspecified

• linux•linux_kernel

  ≥ 5.5.0, < 5.12.2

• netapp•cloud_backup

  na

• netapp•h300e

  na

• netapp•h300s_firmware

  na

• netapp•h410c_firmware

  na

• netapp•h410s_firmware

  na

• netapp•h500e

  na

• netapp•h500s_firmware

  na

• netapp•h700e

  na

• netapp•h700s_firmware

  na

References (3)

• https://xenbits.xenproject.org/xsa/advisory-374.txt
• https://security.gentoo.org/glsa/202107-30
• https://security.netapp.com/advisory/ntap-20210805-0002/