CVE-2023-5717

Description

A heap out-of-bounds write vulnerability in the Linux kernel's Linux Kernel Performance Events (perf) component can be exploited to achieve local privilege escalation. If perf_read_group() is called while an event's sibling_list is smaller than its child's sibling_list, it can increment or write to memory locations outside of the allocated buffer. We recommend upgrading past commit 32671e3799ca2e4590773fd0e63aaa4229e50c06.

From the Ubuntu Security Team

Budimir Markovic discovered that the perf subsystem in the Linux kernel did not properly handle event groups, leading to an out-of-bounds write vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Read the notes from the security team

Why is this CVE medium priority?

Ubuntu kernels enable SECURITY_PERF_EVENTS_RESTRICT which sets kernel.perf_event_paranoid >= 2 and so disables unprivileged users from using perf by default. As such in their default configuration, Ubuntu kernels are not able to be exploited by this flaw to achieve local privilege escalation.

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