Linux Kernel up to 5.13.4 nf_tables null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.13.4. It has been rated as critical. The impacted element is an unknown function of the component nf_tables. Performing a manipulation results in null pointer dereference. This vulnerability was named CVE-2021-47312. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 5.13.4. This affects an unknown function of the component nf_tables. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: Fix dereference of null pointer flow In the case where chain->flags & NFT_CHAIN_HW_OFFLOAD is false then nft_flow_rule_create is not called and flow is NULL. The subsequent error handling execution via label err_destroy_flow_rule will lead to a null pointer dereference on flow when calling nft_flow_rule_destroy. Since the error path to err_destroy_flow_rule has to cater for null and non-null flows, only call nft_flow_rule_destroy if flow is non-null to fix this issue. Addresses-Coverity: ("Explicity null dereference")

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-47312 since 05/21/2024. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 5.13.5 eliminates this vulnerability. Applying the patch 70a5a1950cca/4ca041f919f1 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.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.13.0
• 5.13.1
• 5.13.2
• 5.13.3
• 5.13.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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