CVE-2021-47312 netfilter: nf_tables: Fix dereference of null pointer flow

What is CVE-2021-47312?

CVE-2021-47312 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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")

Weakness: CWE-476

Which versions are affected by CVE-2021-47312?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47312?

No fix has been published for CVE-2021-47312 yet. Limit exposure of the affected software until one is available.

Is CVE-2021-47312 being exploited?

There is no known exploitation of CVE-2021-47312 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-jhg5-q2mj-r9vh, UBUNTU-CVE-2021-47312.