medium5.5
CVE-2021-26933
An issue was discovered in Xen 4.9 through 4.14.x.
Impact
An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Xen | Xen | from 4.9.0 through 4.14.1 |
| Fedoraproject | Fedora | Versions 32, 33 |
| Debian | Debian Linux | Version 10.0 |
References
- NVD record
- CVE.org record
- http://xenbits.xen.org/xsa/advisory-364.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4GELN5E6MDR5KQBJF5M5COUUED3YFZTD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOAJBVAVR6RSCUCHNXPVSNRPSFM7INMP/
- https://www.debian.org/security/2021/dsa-4888
- http://xenbits.xen.org/xsa/advisory-364.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4GELN5E6MDR5KQBJF5M5COUUED3YFZTD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOAJBVAVR6RSCUCHNXPVSNRPSFM7INMP/
- https://www.debian.org/security/2021/dsa-4888