Vulnerability · Published Dec 15, 2020 · Assigned by mitre
CVE-2020-29479
High 8.8
In plain English
A high-severity security flaw in the xen package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation, the internal representation of the tree has special cases for the root node, because this node has no parent. Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.14.1-r0 | ALPINE-CVE-2020-29479 |
| Alpine:v3.21 | xen | 4.14.1-r0 | ALPINE-CVE-2020-29479 |
| Alpine:v3.22 | xen | 4.14.1-r0 | ALPINE-CVE-2020-29479 |
| Alpine:v3.23 | xen | 4.14.1-r0 | ALPINE-CVE-2020-29479 |
| Alpine:v3.24 | xen | 4.14.1-r0 | ALPINE-CVE-2020-29479 |
| Debian:12 | xen | 4.14.0+88-g1d1d1f5391-1 | DEBIAN-CVE-2020-29479 |
| Debian:13 | xen | 4.14.0+88-g1d1d1f5391-1 | DEBIAN-CVE-2020-29479 |
| Debian:14 | xen | 4.14.0+88-g1d1d1f5391-1 | DEBIAN-CVE-2020-29479 |
Affected products (as reported)
References
- https://xenbits.xenproject.org/xsa/advisory-353.html x_refsource_MISC
- DSA-4812 vendor-advisory, x_refsource_DEBIAN
- FEDORA-2020-64859a826b vendor-advisory, x_refsource_FEDORA
- FEDORA-2020-df772b417b vendor-advisory, x_refsource_FEDORA
- GLSA-202107-30 vendor-advisory, x_refsource_GENTOO