DEBIAN-CVE-2020-11739
- Source
- https://security-tracker.debian.org/tracker/DEBIAN-CVE-2020-11739
- Import Source
- https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2020-11739.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/DEBIAN-CVE-2020-11739
- Upstream
- Published
- 2020-04-14T13:15:12Z
- Modified
- 2025-09-19T06:05:37Z
- Summary
- [none]
- Details
-
An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service or possibly gain privileges because of missing memory barriers in read-write unlock paths. The read-write unlock paths don't contain a memory barrier. On Arm, this means a processor is allowed to re-order the memory access with the preceding ones. In other words, the unlock may be seen by another processor before all the memory accesses within the "critical" section. As a consequence, it may be possible to have a writer executing a critical section at the same time as readers or another writer. In other words, many of the assumptions (e.g., a variable cannot be modified after a check) in the critical sections are not safe anymore. The read-write locks are used in hypercalls (such as grant-table ones), so a malicious guest could exploit the race. For instance, there is a small window where Xen can leak memory if XENMAPSPACEgranttable is used concurrently. A malicious guest may be able to leak memory, or cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded.
- References
Affected packages
Debian:11 / xen
Package
- Name
- xen
- Purl
- pkg:deb/debian/xen?arch=source
Debian:12 / xen
Package
- Name
- xen
- Purl
- pkg:deb/debian/xen?arch=source
Debian:13 / xen
Package
- Name
- xen
- Purl
- pkg:deb/debian/xen?arch=source
Debian:14 / xen
Package
- Name
- xen
- Purl
- pkg:deb/debian/xen?arch=source