Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Xen | Xen | >= 4.9.0, <= 4.14.1 |
| Fedoraproject | Fedora | 32 |
| Debian | Debian Linux | 10.0 |
References
- http://xenbits.xen.org/xsa/advisory-364.htmlPatchVendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://www.debian.org/security/2021/dsa-4888Third Party Advisory
- http://xenbits.xen.org/xsa/advisory-364.htmlPatchVendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://www.debian.org/security/2021/dsa-4888Third Party Advisory
FAQ
What is CVE-2021-26933?
CVE-2021-26933 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 t...
How severe is CVE-2021-26933?
CVE-2021-26933 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-26933?
Check the references section above for vendor advisories and patch information. Affected products include: Xen Xen, Fedoraproject Fedora, Debian Debian Linux.