CVE-2020-25084
Description
A use-after-free flaw was found in the USB(xHCI/eHCI) controller emulators of QEMU. This flaw occurs while setting up the USB packet as a usb_packet_map() routine and returns an error that was not checked. This flaw allows a guest user or process to crash the QEMU process, resulting in a denial of service.
Statement
In Red Hat OpenStack Platform, because the flaw has a lower impact and the fix would require a substantial amount of development, no update will be provided at this time for the RHOSP qemu-kvm-rhev package.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.2 | 3.2 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | High | High | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | Low | N/A |
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:C/C:N/I:N/A:L
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
Acknowledgements
Red Hat would like to thank Cornelius Aschermann (Ruhr-University Bochum), Sergej Schumilo (Ruhr-University Bochum), and Simon Wrner (Ruhr-University Bochum) for reporting this issue.
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