PT-2024-11163 · Linux · Linux Kernel

Published 2021-06-07 · Updated 2025-10-02 · CVE-2021-47111

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to the xen-netback component in the Linux kernel, where a reference to the RX task thread needs to be taken to prevent the task from being freed if the thread returns before the call to kthread stop. Not taking this reference can lead to a use-after-free scenario. This reference was previously taken but was dropped as part of a rework. The fix involves reintroducing the reference taking and adding a comment to explain its necessity.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Use After Free

Double Free

Weakness Enumeration

CWE-416

CWE-415

Related Identifiers

BDU:2025-03620

CVE-2021-47111

Affected Products

Linux Kernel

References · 22

• https://osv.dev/vulnerability/DEBIAN-CVE-2021-47111 · Vendor Advisory
• https://git.kernel.org/stable/c/6b53db8c4c14b4e7256f058d202908b54a7b85b4 · Patch
• https://git.kernel.org/stable/c/caec9bcaeb1a5f03f2d406305355c853af10c13e · Patch
• https://git.kernel.org/stable/c/107866a8eb0b664675a260f1ba0655010fac1e08 · Patch
• https://ubuntu.com/security/CVE-2021-47111 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-47111 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47111 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-47111 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-03620 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-47111 · Security Note
• https://osv.dev/vulnerability/CVE-2021-47111 · Vendor Advisory
• https://t.me/cvenotify/73991 · Telegram Post
• https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.43 · Note
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-47111 · Note
• https://git.kernel.org/linus/107866a8eb0b664675a260f1ba0655010fac1e08 · Note