CVE-2020-29485: An issue was discovered in Xen 4.6 through 4.14.x. When acting upon a guest XS_RESET_WATCHES request, not all tracking information is freed. A guest c...

Description

An issue was discovered in Xen 4.6 through 4.14.x. When acting upon a guest XS_RESET_WATCHES request, not all tracking information is freed. A guest can cause unbounded memory usage in oxenstored. This can lead to a system-wide DoS. Only systems using the Ocaml Xenstored implementation are vulnerable. Systems using the C Xenstored implementation are not vulnerable.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.40%

31.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-401

Affected Software

Vendor	Product	Versions
Xen	Xen	>= 4.6.0, <= 4.14.0
Debian	Debian Linux	10.0
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33

References

Timeline

Published: Dec 15, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-29485?

An issue was discovered in Xen 4.6 through 4.14.x. When acting upon a guest XS_RESET_WATCHES request, not all tracking information is freed. A guest can cause unbounded memory usage in oxenstored. This can lead to a system-wide DoS. Only systems using the Ocaml Xenstored implementation are vulnerable. Systems using the C Xenstored implementation are not vulnerable.

How severe is CVE-2020-29485?

CVE-2020-29485 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2020-29485?

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.