CVE-2021-3735
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Description
A deadlock issue was found in the AHCI controller device of QEMU. It occurs on a software reset (ahci_reset_port) while handling a host-to-device Register FIS (Frame Information Structure) packet from the guest. A privileged user inside the guest could use this flaw to hang the QEMU process on the host, resulting in a denial of service condition. The highest threat from this vulnerability is to system availability.
Statement
This issue affects the versions of qemu-kvm as shipped with Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 8 Advanced Virtualization. A future update may address this flaw.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Additional information
- Bugzilla 1997184: QEMU: ahci: deadlock issue leads to denial of service
- CWE-667->CWE-400: Improper Locking leads to Uncontrolled Resource Consumption
- FAQ: Frequently asked questions about CVE-2021-3735
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 3.2 | 4.4 |
Attack Vector | Local | Local |
Attack Complexity | Low | Low |
Privileges Required | High | High |
User Interaction | None | None |
Scope | Changed | Unchanged |
Confidentiality Impact | None | None |
Integrity Impact | None | None |
Availability Impact | Low | High |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Acknowledgements
Red Hat would like to thank Zhiqiang Yan (Tencent Security Yunding Lab) for reporting this issue.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
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