CVE-2021-26933
Fixed in a distro release EPSS <1%
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.
Products: xen, fedoraproject fedora, debian_linux
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine 3.11 | xen | 4.13.2-r5 |
| Alpine 3.12 | xen | 4.13.2-r5 |
| Alpine 3.13 | xen | 4.14.1-r2 |
| Alpine 3.14 | xen | 4.14.1-r3 |
| Alpine 3.15 | xen | 4.14.1-r3 |
| Alpine 3.16 | xen | 4.14.1-r3 |
| Alpine 3.17 | xen | 4.14.1-r3 |
| Alpine 3.18 | xen | 4.14.1-r3 |
| Alpine 3.19 | xen | 4.14.1-r3 |
| Alpine 3.20 | xen | 4.14.1-r3 |
| Alpine 3.21 | xen | 4.14.1-r3 |
| Alpine 3.22 | xen | 4.14.1-r3 |
| Alpine 3.23 | xen | 4.14.1-r3 |
| Alpine 3.24 | xen | 4.14.1-r3 |
| Debian 10 | xen | 4.11.4+99-g8bce4698f6-1 |
| Debian 12 | xen | 4.14.1+11-gb0b734a8b3-1 |
| Debian 13 | xen | 4.14.1+11-gb0b734a8b3-1 |
| Debian 14 | xen | 4.14.1+11-gb0b734a8b3-1 |
| Ubuntu 16.04 LTS | xen | no fix |
| Ubuntu 18.04 LTS | xen | no fix |
| Ubuntu 20.04 LTS | xen | no fix |
| Ubuntu 22.04 LTS | xen | no fix |
| Ubuntu 24.04 LTS | xen | no fix |
| Ubuntu 25.10 | xen | no fix |
| Ubuntu 26.04 LTS | xen | no fix |
| Ubuntu 26.10 | xen | no fix |