CVE-2021-4145: Null Pointer Dereference
First published: Tue Dec 21 2021(Updated: )
A NULL pointer dereference issue was found in the block mirror layer of QEMU in versions prior to 6.2.0. The `self` pointer is dereferenced in mirror_wait_on_conflicts() without ensuring that it's not NULL. A malicious unprivileged user within the guest could use this flaw to crash the QEMU process on the host when writing data reaches the threshold of mirroring node.
Credit: secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| QEMU qemu | =6.1.0 | |
| QEMU qemu | =6.1.0-rc0 | |
| QEMU qemu | =6.1.0-rc1 | |
| QEMU qemu | =6.1.0-rc2 | |
| QEMU qemu | =6.1.0-rc3 | |
| QEMU qemu | =6.1.0-rc4 | |
| Redhat Enterprise Linux | =8.0 |
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Reference Links
Frequently Asked Questions
What is CVE-2021-4145?
CVE-2021-4145 is a vulnerability in the block mirror layer of QEMU in versions prior to 6.2.0.
How severe is CVE-2021-4145?
CVE-2021-4145 has a severity level of 6.5 (medium).
Which software is affected by CVE-2021-4145?
QEMU versions prior to 6.2.0, including qemu-kvm 6.1.0 and earlier on Red Hat Enterprise Linux 8.0.
How can I fix CVE-2021-4145?
To fix CVE-2021-4145, update QEMU to version 6.2.0 or higher.
Where can I find more information about CVE-2021-4145?
For more information about CVE-2021-4145, you can refer to the following references: [Link 1](https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2001404), [Link 2](https://gitlab.com/qemu-project/qemu/-/commit/66fed30c9cd11854fc878a4eceb507e915d7c9cd), [Link 3](https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2035011).
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