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CVE-2021-47225

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: mac80211: fix deadlock in AP/VLAN handling Syzbot reports that when you have AP_VLAN interfaces that are up and close the AP in…

Published May 21, 2024CWE-667EPSS 0.15%

Overview

CVE-2021-47225 is a medium-severity vulnerability. It was published on May 21, 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:

mac80211: fix deadlock in AP/VLAN handling

Syzbot reports that when you have AP_VLAN interfaces that are up

and close the AP interface they belong to, we get a deadlock. No

surprise - since we dev_close() them with the wiphy mutex held,

which goes back into the netdev notifier in cfg80211 and tries to

acquire the wiphy mutex there.

To fix this, we need to do two things:

1) prevent changing iftype while AP_VLANs are up, we can't

easily fix this case since cfg80211 already calls us with

the wiphy mutex held, but change_interface() is relatively

rare in drivers anyway, so changing iftype isn't used much

(and userspace has to fall back to down/change/up anyway)

2) pull the dev_close() loop over VLANs out of the wiphy mutex

section in the normal stop case

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/8043903fcb72f545c52e3ec74d6fd82ef79ce7c5Refgit.kernel.org/stable/c/d5befb224edbe53056c2c18999d630dafb4a08b9Refgit.kernel.org/stable/c/8043903fcb72f545c52e3ec74d6fd82ef79ce7c5Refgit.kernel.org/stable/c/d5befb224edbe53056c2c18999d630dafb4a08b9

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47225?

CVE-2021-47225 is a medium-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47225?

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-2021-47225?

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-2021-47225?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47225 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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