CVE-2021-3929: Use After Free
First published: Thu Nov 04 2021(Updated: )
A DMA reentrancy issue was found in the NVM Express Controller (NVME) emulation in QEMU. This CVE is similar to CVE-2021-3750 and, just like it, when the reentrancy write triggers the reset function nvme_ctrl_reset(), data structs will be freed leading to a use-after-free issue. A malicious guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition or, potentially, executing arbitrary code within the context of the QEMU process on the host.
Credit: secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| QEMU qemu | <7.0.0 | |
| Fedoraproject Fedora | =35 | |
| Fedoraproject Fedora | =36 | |
| ubuntu/qemu | <1:6.2+dfsg-2ubuntu6.2 | 1:6.2+dfsg-2ubuntu6.2 |
| redhat/qemu-kvm | <7.0.0 | 7.0.0 |
| debian/qemu | <=1:5.2+dfsg-11+deb11u3<=1:5.2+dfsg-11+deb11u2 | 1:3.1+dfsg-8+deb10u8 1:3.1+dfsg-8+deb10u11 1:7.2+dfsg-7+deb12u3 1:8.2.1+ds-1 |
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Reference Links
- https://access.redhat.com/security/cve/CVE-2021-3929
- https://bugzilla.redhat.com/show_bug.cgi?id=2020298
- https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385
- https://gitlab.com/qemu-project/qemu/-/issues/556
- https://gitlab.com/qemu-project/qemu/-/issues/782
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XHNN7QJCEQH7AQG5AQP2GEFAQE6K635I/
- https://launchpad.net/bugs/cve/CVE-2021-3929
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XHNN7QJCEQH7AQG5AQP2GEFAQE6K635I/
- https://access.redhat.com/security/cve/CVE-2021-3750
- https://access.redhat.com/security/cve/cve-2021-3929
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2020298#c0
- https://access.redhat.com/solutions/408653
- https://lists.nongnu.org/archive/html/qemu-devel/2021-08/msg03927.html
- https://gitlab.com/qemu-project/qemu/-/issues/782#reproducer
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2066083
- https://lists.nongnu.org/archive/html/qemu-devel/2021-08/msg03692.html
- https://lists.nongnu.org/archive/html/qemu-devel/2022-01/msg04577.html
- https://gitlab.com/qemu-project/qemu/-/commit/736b01642d85be832385063f278fe7cd4ffb5221
- https://security-tracker.debian.org/tracker/CVE-2021-3929
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3929
- https://ubuntu.com/security/notices/USN-5489-1
- https://nvd.nist.gov/vuln/detail/CVE-2021-3929
- https://git.qemu.org/?p=qemu.git;a=commit;h=736b01642d85be832385063f278fe7cd4ffb5221
- https://ubuntu.com/security/CVE-2021-3929
Frequently Asked Questions
What is CVE-2021-3929?
CVE-2021-3929 is a DMA reentrancy issue found in the NVM Express Controller (NVME) emulation in QEMU.
How does CVE-2021-3929 affect QEMU?
CVE-2021-3929 can lead to a use-after-free issue in QEMU when the reentrancy write triggers the reset function nvme_ctrl_reset().
What is the severity of CVE-2021-3929?
CVE-2021-3929 has a severity rating of 8.2 (high).
Which software versions are affected by CVE-2021-3929?
QEMU versions 1:6.2+dfsg-2ubuntu6.2 (Ubuntu), 1:3.1+dfsg-8+deb10u8/1:3.1+dfsg-8+deb10u11 (Debian), 1:7.2+dfsg-7+deb12u2/1:8.1.1+ds-2/1:8.1.2+ds-1 (Debian), QEMU qemu 7.0.0 (CPE), Fedora 35 and Fedora 36 (Fedoraproject Fedora), and qemu-kvm 7.0.0 (Red Hat) are affected.
How can I fix CVE-2021-3929?
To fix CVE-2021-3929, users should update to the recommended software versions provided by their respective vendors.
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