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CVE-2021-47462

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind() syzbot reported access to unitialized memory i…

Published May 22, 2024CWE-908EPSS 0.18%

Overview

CVE-2021-47462 is a medium-severity vulnerability. It was published on May 22, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind()

syzbot reported access to unitialized memory in mbind() [1]

Issue came with commit bda420b98505 ("numa balancing: migrate on fault

among multiple bound nodes")

This commit added a new bit in MPOL_MODE_FLAGS, but only checked valid

combination (MPOL_F_NUMA_BALANCING can only be used with MPOL_BIND) in

do_set_mempolicy()

This patch moves the check in sanitize_mpol_flags() so that it is also

used by mbind()

[1]

BUG: KMSAN: uninit-value in __mpol_equal+0x567/0x590 mm/mempolicy.c:2260

__mpol_equal+0x567/0x590 mm/mempolicy.c:2260

mpol_equal include/linux/mempolicy.h:105 [inline]

vma_merge+0x4a1/0x1e60 mm/mmap.c:1190

mbind_range+0xcc8/0x1e80 mm/mempolicy.c:811

do_mbind+0xf42/0x15f0 mm/mempolicy.c:1333

kernel_mbind mm/mempolicy.c:1483 [inline]

__do_sys_mbind mm/mempolicy.c:1490 [inline]

__se_sys_mbind+0x437/0xb80

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/6d2aec9e123bb9c49cb5c7fc654f25f81e688e8cRefgit.kernel.org/stable/c/9ee4e9ae98f1f262d6fae0d266cfdf3ba2c321d9Refgit.kernel.org/stable/c/6d2aec9e123bb9c49cb5c7fc654f25f81e688e8cRefgit.kernel.org/stable/c/9ee4e9ae98f1f262d6fae0d266cfdf3ba2c321d9

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47462?

CVE-2021-47462 is a medium-severity vulnerability. It was published on May 22, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47462?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47462?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47462?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47462 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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