Description
In the Linux kernel, the following vulnerability has been resolved:
xen-netback: take a reference to the RX task thread
Do this in order to prevent the task from being freed if the thread
returns (which can be triggered by the frontend) before the call to
kthread_stop done as part of the backend tear down. Not taking the
reference will lead to a use-after-free in that scenario. Such
reference was taken before but dropped as part of the rework done in
2ac061ce97f4.
Reintroduce the reference taking and add a comment this time
explaining why it's needed.
This is XSA-374 / CVE-2021-28691.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.5 | 5.10.43 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 5.10.46-1 | — |
| Debian 13 | linux | 5.10.46-1 | — |
| Debian 12 | linux | 5.10.46-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | linux-riscv +20 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +26 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |