Risk | Low |
Patch available | YES |
Number of vulnerabilities | 1 |
CVE-ID | CVE-2020-29566 |
CWE-ID | CWE-674 |
Exploitation vector | Local |
Public exploit | N/A |
Vulnerable software Subscribe |
Xen Server applications / Virtualization software |
Vendor | Xen Project |
Security Bulletin
This security bulletin contains one low risk vulnerability.
EUVDB-ID: #VU49137
Risk: Low
CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-29566
CWE-ID:
CWE-674 - Uncontrolled Recursion
Exploit availability: No
DescriptionThe vulnerability allows a local authenticated user to perform a denial of service (DoS) attack.
An issue was discovered in Xen through 4.14.x. When they require assistance from the device model, x86 HVM guests must be temporarily de-scheduled. The device model will signal Xen when it has completed its operation, via an event channel, so that the relevant vCPU is rescheduled. If the device model were to signal Xen without having actually completed the operation, the de-schedule / re-schedule cycle would repeat. If, in addition, Xen is resignalled very quickly, the re-schedule may occur before the de-schedule was fully complete, triggering a shortcut. This potentially repeating process uses ordinary recursive function calls, and thus could result in a stack overflow. A malicious or buggy stubdomain serving a HVM guest can cause Xen to crash, resulting in a Denial of Service (DoS) to the entire host. Only x86 systems are affected. Arm systems are not affected. Only x86 stubdomains serving HVM guests can exploit the vulnerability.
MitigationInstall update from vendor's website.
Vulnerable software versionsXen: 4.0.0 - 4.14.1
External linkshttp://www.debian.org/security/2020/dsa-4812
http://xenbits.xenproject.org/xsa/advisory-348.html
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.