PT-2021-8255 · Linux · Linux Kernel

Maxim Galaganov · Published 2021-06-10 · Updated 2024-07-08 · CVE-2021-47242

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:N/UI:R/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 a soft lookup in the subflow error report() function of the Linux kernel's mptcp component. This can cause a soft lockup when the function tries to acquire the mptcp data lock from different contexts, such as plain ssk socket lock, ssk socket lock + mptcp data lock, or ssk socket lock + mptcp data lock + msk socket lock. The problem is addressed by moving the error reporting call to outer functions where the held locks list is known, allowing only the necessary locks to be acquired.

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

Improper Locking

Weakness Enumeration

CWE-667

Related Identifiers

BDU:2025-00793

CVE-2021-47242

Affected Products

Linux Kernel

References · 14

• https://git.kernel.org/stable/c/499ada5073361c631f2a3c4a8aed44d53b6f82ec · Patch
• https://security-tracker.debian.org/tracker/CVE-2021-47242 · Vendor Advisory
• https://git.kernel.org/stable/c/27ef25c72373222aaa5fe7b5cd890ae9cfb89a8d · Patch
• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-47242 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-47242 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-47242 · Security Note
• https://ubuntu.com/security/CVE-2021-47242 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47242 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-00793 · Security Note
• https://git.kernel.org/linus/499ada5073361c631f2a3c4a8aed44d53b6f82ec · Note
• https://access.redhat.com/security/cve/CVE-2021-47242 · Note
• https://twitter.com/CVEnew/status/1792928075832828178 · Twitter Post
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=499ada5073361c631f2a3c4a8aed44d53b6f82ec · Note