CVE-2015-6855
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Description
It has been discovered that a QEMU emulator built with IDE disk and CD/DVD-ROM emulation support is vulnerable to a divide-by-zero issue. The flaw could occur when executing IDE's WIN_READ_NATIVE_MAX command to determine the maximum size of a drive. A privileged user inside the guest could use this flaw to crash the QEMU instance, resulting in a denial of service.
Statement
This issue affects the versions of kvm and xen packages as shipped with Red Hat Enterprise Linux 5.
This issue affects the versions of the qemu-kvm packages as shipped with Red Hat Enterprise Linux 6 and 7.
This issue affects the Red Hat Enterprise Linux 6 based versions of qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
This issue affect the Red Hat Enterprise Linux 7 based versions of the qemu-kvm-rhev packages as shipped with Red Hat Enterprise Virtualization 3.
Additional information
- Bugzilla 1260080: Qemu: ide: divide by zero issue
- CWE-369: Divide By Zero
- FAQ: Frequently asked questions about CVE-2015-6855
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 v2 Base Score | 2.3 | 5 |
Attack Vector | Adjacent Network | Network |
Access Complexity | Medium | Low |
Authentication | Single | None |
Confidentiality Impact | None | None |
Integrity Impact | None | None |
Availability Impact | Partial | Partial |
CVSS v2 Vector
Red Hat: AV:A/AC:M/Au:S/C:N/I:N/A:P
NVD: AV:N/AC:L/Au:N/C:N/I:N/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
A Divide by Zero results in a crash.
Acknowledgements
Red Hat would like to thank Qinghao Tang (QIHU 360 Inc) 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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