CVE-2023-4732: Kernel: race between task migrating pages and another task calling exit_mmap to release those same pages getting invalid opcode bug in include/linux/swapops.h
A flaw was found in pfnswapentrytopage in memory management subsystem in the Linux Kernel. In this flaw, an attacker with a local user privilege may cause a denial of service problem due to a BUG statement referencing pmdt x.
Other sources
A flaw was found in the Linux Kernel's memory management subsytem. In this flaw, A task is exiting and releasing 2MB page in a vma (vmareastruct) and hits the BUG statement in pfnswapentrytopage() referencing pmdt x.
208 static inline struct page pfnswapentrytopage(swpentryt entry) 209 { <omit> 216 BUGON(ismigrationentry(entry) && !PageLocked(p)); <-----
It finds the entry is of type SWPMIGRATIONREAD and the page is not locked, Another task is calling migratepages() on the same addresses and has just completed with the above pmdt x and is moving to pmdt x+1 in trytounmapone().
— Red Hat
Linux Kernel is vulnerable to a denial of service, caused by a race condition between task migrating pages and another task calling exitmmap to release those same pages getting invalid opcode BUG in include/linux/swapops.h in the memory management subsytem. A local authenticated attacker could exploit this vulnerability to cause a denial of service.
— IBM
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2023-4732?
The severity of CVE-2023-4732 is medium with a CVSS score of 4.7.
What is the affected software for CVE-2023-4732?
The affected software for CVE-2023-4732 includes the Linux Kernel version up to and including 5.13.19, and Redhat Enterprise Linux 8.0.
How can an attacker exploit CVE-2023-4732?
An attacker with local user privilege can exploit CVE-2023-4732 by causing a denial of service problem through a BUG statement referencing pmd_t x in the Linux Kernel's memory management subsystem.
How can I fix CVE-2023-4732?
To fix CVE-2023-4732, update your Linux Kernel to version 5.14 or apply the appropriate remedy provided by Redhat.
Where can I find more information about CVE-2023-4732?
You can find more information about CVE-2023-4732 in the references provided: [1](https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2236982#c1), [2](https://bugzilla.redhat.com/show_bug.cgi?id=2236982), [3](https://access.redhat.com/security/cve/CVE-2023-4732)