Linux Kernel up to 5.12.3 emac-mac emac_tx_fill_tpd use after free

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.12.3. It has been classified as problematic. Affected by this vulnerability is the function emac_tx_fill_tpd of the component emac-mac. Performing a manipulation results in use after free. This vulnerability is reported as CVE-2021-47013. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.12.3 (Operating System). It has been classified as problematic. This affects the function emac_tx_fill_tpd of the component emac-mac. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. The impact remains unknown. The summary by CVE is:

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.

The weakness was disclosed 02/28/2024. The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-47013 since 02/27/2024. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/09/2024).

Upgrading to version 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4 or 5.13 eliminates this vulnerability. Applying the patch c7f75d11fe72/dc1b438a3577/16d8c44be52e/55fcdd1258fa/9dc373f74097/8c06f3478506/e407495ba678/6d72e7c767ac is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.9.268
• 4.14.232
• 4.19.190
• 5.4.118
• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
• 5.10.15
• 5.10.16
• 5.10.17
• 5.10.18
• 5.10.19
• 5.10.20
• 5.10.21
• 5.10.22
• 5.10.23
• 5.10.24
• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.10.35
• 5.10.36
• 5.11.0
• 5.11.1
• 5.11.2
• 5.11.3
• 5.11.4
• 5.11.5
• 5.11.6
• 5.11.7
• 5.11.8
• 5.11.9
• 5.11.10
• 5.11.11
• 5.11.12
• 5.11.13
• 5.11.14
• 5.11.15
• 5.11.16
• 5.11.17
• 5.11.18
• 5.11.19
• 5.11.20
• 5.12.0
• 5.12.1
• 5.12.2
• 5.12.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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CVSSv4info

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Exploitinginfo

Threat Intelligenceinfo

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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