CVE-2021-47111

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinux2ac061ce97f413bfbbdd768f7d2e0fda2e8170df < 6b53db8c4c14b4e7256f058d202908b54a7b85b4affected
LinuxLinux2ac061ce97f413bfbbdd768f7d2e0fda2e8170df < caec9bcaeb1a5f03f2d406305355c853af10c13eaffected
LinuxLinux2ac061ce97f413bfbbdd768f7d2e0fda2e8170df < 107866a8eb0b664675a260f1ba0655010fac1e08affected
LinuxLinux5.5affected
LinuxLinux0 < 5.5unaffected
LinuxLinux5.10.43 <= 5.10.*unaffected
LinuxLinux5.12.10 <= 5.12.*unaffected
LinuxLinux5.13 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References