CVE-2021-47111

HighCVSS 7.8/10Last modified Aug 4, 2026

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.

Metrics

CVSS 3.1 7.8/10CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness enumeration

CWE-416

Affected software

VendorProductVersions
LinuxLinux>= 2ac061ce97f413bfbbdd768f7d2e0fda2e8170df, < 6b53db8c4c14b4e7256f058d202908b54a7b85b4; >= 2ac061ce97f413bfbbdd768f7d2e0fda2e8170df, < caec9bcaeb1a5f03f2d406305355c853af10c13e; >= 2ac061ce97f413bfbbdd768f7d2e0fda2e8170df, < 107866a8eb0b664675a260f1ba0655010fac1e08
LinuxLinux5.5

References

Timeline

Published
Mar 15, 2024
Last modified
Aug 4, 2026
NVD status
Modified

Related CVEs from 2021

CVE-2021-471125.5In the Linux kernel, the following vulnerability has been resolved: x86/kvm: Teardown PV features on boot CPU as well Various PV features CVE-2021-471135.5In the Linux kernel, the following vulnerability has been resolved: btrfs: abort in rename_exchange if we fail to insert the second ref ErCVE-2021-471145.5In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes oCVE-2021-471165.5In the Linux kernel, the following vulnerability has been resolved: ext4: fix memory leak in ext4_mb_init_backend on error path. Fix a memCVE-2021-471175.5In the Linux kernel, the following vulnerability has been resolved: ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failedCVE-2021-471187.8In the Linux kernel, the following vulnerability has been resolved: pid: take a reference when initializing `cad_pid` During boot, kernel_CVE-2021-471195.5In the Linux kernel, the following vulnerability has been resolved: ext4: fix memory leak in ext4_fill_super Buffer head references must bCVE-2021-471205.5In the Linux kernel, the following vulnerability has been resolved: HID: magicmouse: fix NULL-deref on disconnect Commit 9d7b18668956 ("HICVE-2021-471215.5In the Linux kernel, the following vulnerability has been resolved: net: caif: fix memory leak in cfusbl_device_notify In case of caif_enrCVE-2021-471225.5In the Linux kernel, the following vulnerability has been resolved: net: caif: fix memory leak in caif_device_notify In case of caif_enrolCVE-2021-471237.8In the Linux kernel, the following vulnerability has been resolved: io_uring: fix ltout double free on completion race Always remove linkeCVE-2021-471245.5In the Linux kernel, the following vulnerability has been resolved: io_uring: fix link timeout refs WARNING: CPU: 0 PID: 10242 at lib/refc
CVE-2021-47111: High severity, CVSS 7.8 | Vulnix