SB2021062915 - Use after free in Linux kernel

Description

This security bulletin contains information about 1 security vulnerability.

1) Use after free (CVE-ID: CVE-2021-28691)

The vulnerability allows a local user to execute arbitrary code.

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.

Remediation

Install update from vendor's website.

References

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