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CVE-2021-47013

9.8 · CRITICAL

In the Linux kernel, the following vulnerability has been resolved: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..).

Published Feb 28, 2024CWE-416EPSS 0.79%

Overview

CVE-2021-47013 is a critical-severity vulnerability. It was published on February 28, 2024 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

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

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..).

If some error happens in emac_tx_fill_tpd(), the skb will be freed via

dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd().

But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len).

As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len,

thus my patch assigns skb->len to 'len' before the possible free and

use 'len' instead of skb->len later.

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/16d8c44be52e3650917736d45f5904384a9da834Refgit.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775dRefgit.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57Refgit.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7Refgit.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99dRefgit.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955Refgit.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322Refgit.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879bRefgit.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834Refgit.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47013?

CVE-2021-47013 is a critical-severity vulnerability. It was published on February 28, 2024 and has a CVSS 3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2021-47013?

This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-47013?

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-2021-47013?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47013 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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