CVE-2021-47013
Linux Kernel use-after-free
- Published28 Feb 2024
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
Remediation
- 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
References
- 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
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2021-47013 being actively exploited?
CVE-2021-47013 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.79%.
How severe is CVE-2021-47013?
CVE-2021-47013 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.79% probability of exploitation.
Which products are affected by CVE-2021-47013?
Affected products include Linux Kernel.
How do I fix CVE-2021-47013?
Upgrade affected software to a fixed version, for example Linux Kernel 4.14.233 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2021-47013 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.