CVE-2021-47461

userfaultfd: fix a race between writeprotect and exit_mmap()

Description

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a race between writeprotect and exit_mmap() A race is possible when a process exits, its VMAs are removed by exit_mmap() and at the same time userfaultfd_writeprotect() is called. The race was detected by KASAN on a development kernel, but it appears to be possible on vanilla kernels as well. Use mmget_not_zero() to prevent the race as done in other userfaultfd operations.

N/A

CVSS

Severity:

EPSS 0.17%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/3cda4bfffd4f755645577aaa9e96a606657b4525
https://git.kernel.org/stable/c/149958ecd0627a9f1e9c678c25c665400054cd6a
https://git.kernel.org/stable/c/cb185d5f1ebf900f4ae3bf84cee212e6dd035aca

Frequently Asked Questions

What is the severity of CVE-2021-47461?: CVE-2021-47461 has not yet been assigned a CVSS score.
How to fix CVE-2021-47461?: To fix CVE-2021-47461, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47461 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2021-47461 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47461?: CVE-2021-47461 affects Linux Linux, Linux Linux.

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