CVE-2020-35517: High severity Qemu Qemu vulnerability
A flaw was found in qemu. A host privilege escalation issue was found in the virtio-fs shared file system daemon where a privileged guest user is able to create a device special file in the shared directory and use it to r/w access host devices.
Other sources
A potential host privilege escalation issue was found in the virtio-fs shared file system daemon (virtiofsd) of the QEMU. Virtio-fs daemon shares host directory tree with a guest VM. The said privilege escalation scenario may occur if a privileged guest user was to create device special file in the shared directory and use it to r/w access host devices. A privileged guest user may use this flaw to arbitrarily access (r/w) host files resulting in DoS scenario or may potentially reach privilege escalation on the host.
Upstream patch: --------------- -> https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg05461.html
— Red Hat
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/qemuto a version that resolves this vulnerability.Fixed in 1:5.2+dfsg-11+deb11u3Fixed in 1:5.2+dfsg-11+deb11u2Fixed in 1:7.2+dfsg-7+deb12u12Fixed in 1:10.0.0~rc2+ds-2Fixed in 1:10.0.0~rc3+ds-2 - Upgrade
Upgrade
alpine/qemuto a version that resolves this vulnerability.Fixed in 5.2.0-r0
Event History
Frequently Asked Questions
What is CVE-2020-35517?
CVE-2020-35517 is a vulnerability in qemu that allows a privileged guest user to create a device special file in the shared directory and use it to read/write access host devices, leading to a host privilege escalation.
What is the severity of CVE-2020-35517?
The severity of CVE-2020-35517 is high with a CVSS score of 8.2.
How does CVE-2020-35517 affect QEMU?
CVE-2020-35517 affects QEMU versions 5.0.0 to 5.2.50 and potentially allows a privileged guest user to gain host privilege by creating a device special file in the shared directory.
How can I fix CVE-2020-35517 on Ubuntu?
To fix CVE-2020-35517 on Ubuntu, update the `qemu` package to version 1:5.2+dfsg-6ubuntu2 or later.
How can I fix CVE-2020-35517 on Debian?
To fix CVE-2020-35517 on Debian, update the `qemu` package to the latest available version.