CVE-2021-26933
medium
CVSS v3
—
CVSS v2
—
VIR risk
5.5
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.
Predictions
Exploit likelihood
20%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-26933
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| arch | affected | | |
| debian | bookworm | fixed | 4.14.1+11-gb0b734a8b3-1 |
| debian | bullseye | fixed | 4.14.1+11-gb0b734a8b3-1 |
| debian | forky | fixed | 4.14.1+11-gb0b734a8b3-1 |
| debian | sid | fixed | 4.14.1+11-gb0b734a8b3-1 |
| debian | trixie | fixed | 4.14.1+11-gb0b734a8b3-1 |
References
Verify integrity in audit chain (admin only). AS-IS.