CVE-2019-19582: An issue was discovered in Xen through 4.12.x allowing x86 guest OS users to cause a denial of service (infinite loop) because certain bit iteration i...

Description

An issue was discovered in Xen through 4.12.x allowing x86 guest OS users to cause a denial of service (infinite loop) because certain bit iteration is mishandled. In a number of places bitmaps are being used by the hypervisor to track certain state. Iteration over all bits involves functions which may misbehave in certain corner cases: On x86 accesses to bitmaps with a compile time known size of 64 may incur undefined behavior, which may in particular result in infinite loops. A malicious guest may cause a hypervisor crash or hang, resulting in a Denial of Service (DoS). All versions of Xen are vulnerable. x86 systems with 64 or more nodes are vulnerable (there might not be any such systems that Xen would run on). x86 systems with less than 64 nodes are not vulnerable.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

EPSS Probability

0.38%

29.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions
Xen	Xen	>= 4.8.0, <= 4.12.1
Fedoraproject	Fedora	31

References

Timeline

Published: Dec 11, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-19582?

An issue was discovered in Xen through 4.12.x allowing x86 guest OS users to cause a denial of service (infinite loop) because certain bit iteration is mishandled. In a number of places bitmaps are being used by the hypervisor to track certain state. Iteration over all bits involves functions which may misbehave in certain corner cases: On x86 accesses to bitmaps with a compile time known size of 64 may incur undefined behavior, which may in particular result in infinite loops. A malicious guest may cause a hypervisor crash or hang, resulting in a Denial of Service (DoS). All versions of Xen are vulnerable. x86 systems with 64 or more nodes are vulnerable (there might not be any such systems that Xen would run on). x86 systems with less than 64 nodes are not vulnerable.

How severe is CVE-2019-19582?

CVE-2019-19582 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.38% probability of exploitation in the next 30 days.

How do I fix CVE-2019-19582?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.