CVE-2021-47013

HIGH
Published Feb 28, 2024 Modified Dec 9, 2024 CWE-416

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.

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CVSS v3.1 Score

7.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834 https://git.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d https://git.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57 https://git.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7 https://git.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99d https://git.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955 https://git.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322 https://git.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879b https://git.kernel.org/stable/c/16d8c44be52e3650917736d45f5904384a9da834 https://git.kernel.org/stable/c/55fcdd1258faaecca74b91b88cc0921f9edd775d https://git.kernel.org/stable/c/6d72e7c767acbbdd44ebc7d89c6690b405b32b57 https://git.kernel.org/stable/c/8c06f34785068b87e2b560534c77c163d6c6dca7 https://git.kernel.org/stable/c/9dc373f74097edd0e35f3393d6248eda8d1ba99d https://git.kernel.org/stable/c/c7f75d11fe72913d2619f97b2334b083cd7bb955 https://git.kernel.org/stable/c/dc1b438a35773d030be0ee80d9c635c3e558a322 https://git.kernel.org/stable/c/e407495ba6788a67d1bd41714158c079e340879b

Frequently Asked Questions

What is CVE-2021-47013? +
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. It has a CVSS v3.1 base score of 7.8 (HIGH).
How severe is CVE-2021-47013? +
CVE-2021-47013 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2021-47013? +
CVE-2021-47013 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47013? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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