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CVE-2021-47223

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix vlan tunnel dst null pointer dereference This patch fixes a tunnel_dst null pointer dereference due to lockles…

Published May 21, 2024CWE-476EPSS 0.24%

Overview

CVE-2021-47223 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:

net: bridge: fix vlan tunnel dst null pointer dereference

This patch fixes a tunnel_dst null pointer dereference due to lockless

access in the tunnel egress path. When deleting a vlan tunnel the

tunnel_dst pointer is set to NULL without waiting a grace period (i.e.

while it's still usable) and packets egressing are dereferencing it

without checking. Use READ/WRITE_ONCE to annotate the lockless use of

tunnel_id, use RCU for accessing tunnel_dst and make sure it is read

only once and checked in the egress path. The dst is already properly RCU

protected so we don't need to do anything fancy than to make sure

tunnel_id and tunnel_dst are read only once and checked in the egress path.

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/24a6e55f17aa123bc1fc54b7d3c410b41bc16530Refgit.kernel.org/stable/c/58e2071742e38f29f051b709a5cca014ba51166fRefgit.kernel.org/stable/c/a2241e62f6b4a774d8a92048fdf59c45f6c2fe5cRefgit.kernel.org/stable/c/abb02e05cb1c0a30dd873a29f33bc092067dc35dRefgit.kernel.org/stable/c/ad7feefe7164892db424c45687472db803d87f79Refgit.kernel.org/stable/c/fe0448a3fad365a747283a00a1d1ad5e8d6675b7Refgit.kernel.org/stable/c/24a6e55f17aa123bc1fc54b7d3c410b41bc16530Refgit.kernel.org/stable/c/58e2071742e38f29f051b709a5cca014ba51166fRefgit.kernel.org/stable/c/a2241e62f6b4a774d8a92048fdf59c45f6c2fe5cRefgit.kernel.org/stable/c/abb02e05cb1c0a30dd873a29f33bc092067dc35d

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47223?

CVE-2021-47223 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-2021-47223?

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-2021-47223?

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-2021-47223?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47223 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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