CVE-2020-35503 : Security Advisory and Response
Learn about CVE-2020-35503, a vulnerability in QEMU versions before and including 6.0 that allows a privileged guest user to crash the QEMU process, leading to a denial of service. Find mitigation steps and prevention measures here.
A NULL pointer dereference flaw in the megasas-gen2 SCSI host bus adapter emulation of QEMU allows a privileged guest user to crash the QEMU process, leading to a denial of service.
Understanding CVE-2020-35503
This CVE identifies a vulnerability in QEMU versions before and including 6.0 that can be exploited by a privileged guest user to cause a denial of service on the host system.
What is CVE-2020-35503?
This vulnerability involves a NULL pointer dereference issue in the megasas-gen2 SCSI host bus adapter emulation of QEMU. The flaw occurs in the megasas_command_cancelled() callback function when dropping a SCSI request.
The Impact of CVE-2020-35503
The primary risk posed by this vulnerability is the potential for a privileged guest user to crash the QEMU process on the host, resulting in a denial of service condition that affects system availability.
Technical Details of CVE-2020-35503
This section provides more in-depth technical information about the vulnerability.
Vulnerability Description
A NULL pointer dereference flaw in the megasas-gen2 SCSI host bus adapter emulation of QEMU allows a privileged guest user to crash the QEMU process, leading to a denial of service.
Affected Systems and Versions
- Product: QEMU
- Vendor: n/a
- Versions affected: All QEMU versions before and including 6.0
Exploitation Mechanism
The vulnerability can be exploited by a privileged guest user through the megasas_command_cancelled() callback function while dropping a SCSI request.
Mitigation and Prevention
Protecting systems from CVE-2020-35503 requires immediate action and long-term security practices.
Immediate Steps to Take
- Apply patches or updates provided by the vendor to address the vulnerability.
- Monitor vendor sources for security advisories and apply relevant patches promptly.
Long-Term Security Practices
- Regularly update and patch software to mitigate known vulnerabilities.
- Implement least privilege access controls to limit the impact of potential exploits.
Patching and Updates
Ensure that all QEMU installations are updated to version 6.0 or higher to mitigate the vulnerability.