CVE-2017-13673
Description
An assert failure issue was found in the VGA display emulator built into the Quick emulator (QEMU). It could occur while updating graphics display, due to miscalculating region for dirty bitmap snapshot in split screen mode. A privileged user/process inside guest could use this flaw to crash the QEMU process on the host resulting in denial of service.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3 | 6.5 | N/A |
| Attack Vector | Adjacent Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:A/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:L
NVD: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 2.3 | 4 | N/A |
| Attack Vector | Adjacent Network | Network | N/A |
| Access Complexity | Medium | Low | N/A |
| Authentication | Single | Single | N/A |
| Confidentiality Impact | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Partial | Partial | N/A |
Vector
Red Hat: AV:A/AC:M/Au:S/C:N/I:N/A:P
NVD: AV:N/AC:L/Au:S/C:N/I:N/A:P
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, an attacker can still cause a denial of service if they can trigger an assert statement, and if the scope of the assert() extends beyond the attacker's own session. For example, if a server handles multiple simultaneous connections, if an assert() occurs in one single connection that causes all other connections to be dropped, this could be a significant denial of service.
Acknowledgements
Red Hat would like to thank David Buchanan for reporting this issue.
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