CVE-2021-47111

xen-netback: take a reference to the RX task thread

Severity Score

"-"

*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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.

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: xen-netback: toma una referencia al hilo de la tarea RX. Haga esto para evitar que la tarea se libere si el hilo regresa (que puede ser activado por el frontend) antes de que llamada a kthread_stop realizada como parte del desmontaje del backend. No tomar la referencia conducirá a un use-after-free en ese escenario. Esta referencia se tomó antes, pero se eliminó como parte de la revisión realizada en 2ac061ce97f4. Vuelva a introducir la toma de referencia y agregue esta vez un comentario explicando por qué es necesario. Este es XSA-374/CVE-2021-28691.

*Credits: N/A

CVSS Scores

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-03-04 CVE Reserved
2024-03-15 CVE Published
2024-03-16 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (4)

URL	Tag	Source
https://git.kernel.org/stable/c/2ac061ce97f413bfbbdd768f7d2e0fda2e8170df	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/6b53db8c4c14b4e7256f058d202908b54a7b85b4	2021-06-10
https://git.kernel.org/stable/c/caec9bcaeb1a5f03f2d406305355c853af10c13e	2021-06-10
https://git.kernel.org/stable/c/107866a8eb0b664675a260f1ba0655010fac1e08	2021-06-07

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.5 < 5.10.43 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.5 < 5.10.43"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.5 < 5.12.10 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.5 < 5.12.10"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				>= 5.5 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.5 < 5.13"		en		Affected