Linux Kernel up to 5.10.10 netif_rx_ni use after free

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 5.10.10. The impacted element is the function netif_rx_ni. Performing a manipulation results in use after free. This vulnerability is known as CVE-2021-47668. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.10.10. It has been classified as critical. This affects the function netif_rx_ni. 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: can: dev: can_restart: fix use after free bug After calling netif_rx_ni(skb), dereferencing skb is unsafe. Especially, the can_frame cf which aliases skb memory is accessed after the netif_rx_ni() in: stats->rx_bytes += cf->len; Reordering the lines solves the issue.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-47668 since 04/16/2025. The exploitability is told to be easy. 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 02/16/2026).

Upgrading to version 4.4.254, 4.9.254, 4.14.218, 4.19.171, 5.4.93 or 5.10.11 eliminates this vulnerability. Applying the patch 260925a0b7d2da5449f8ecfd02c1405e0c8a45b8/bbc6847b9b8978b520f62fbc7c68c54ef0f8d282/92668d28c7e6a7a2ba07df287669ffcdf650c421/08ab951787098ae0b6c0364aeea7a8138226f234/ac48ef15826e83f4206c47add61072e8fc76d328/593c072b7b3c4d7044416eb039d9ad706bedd67a/03f16c5075b22c8902d2af739969e878b0879c94 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.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2025-0861). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• SolarWinds Security Event Manager
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.4.253
• 4.9.253
• 4.14.217
• 4.19.170
• 5.4.0
• 5.4.1
• 5.4.2
• 5.4.3
• 5.4.4
• 5.4.5
• 5.4.6
• 5.4.7
• 5.4.8
• 5.4.9
• 5.4.10
• 5.4.11
• 5.4.12
• 5.4.13
• 5.4.14
• 5.4.15
• 5.4.16
• 5.4.17
• 5.4.18
• 5.4.19
• 5.4.20
• 5.4.21
• 5.4.22
• 5.4.23
• 5.4.24
• 5.4.25
• 5.4.26
• 5.4.27
• 5.4.28
• 5.4.29
• 5.4.30
• 5.4.31
• 5.4.32
• 5.4.33
• 5.4.34
• 5.4.35
• 5.4.36
• 5.4.37
• 5.4.38
• 5.4.39
• 5.4.40
• 5.4.41
• 5.4.42
• 5.4.43
• 5.4.44
• 5.4.45
• 5.4.46
• 5.4.47
• 5.4.48
• 5.4.49
• 5.4.50
• 5.4.51
• 5.4.52
• 5.4.53
• 5.4.54
• 5.4.55
• 5.4.56
• 5.4.57
• 5.4.58
• 5.4.59
• 5.4.60
• 5.4.61
• 5.4.62
• 5.4.63
• 5.4.64
• 5.4.65
• 5.4.66
• 5.4.67
• 5.4.68
• 5.4.69
• 5.4.70
• 5.4.71
• 5.4.72
• 5.4.73
• 5.4.74
• 5.4.75
• 5.4.76
• 5.4.77
• 5.4.78
• 5.4.79
• 5.4.80
• 5.4.81
• 5.4.82
• 5.4.83
• 5.4.84
• 5.4.85
• 5.4.86
• 5.4.87
• 5.4.88
• 5.4.89
• 5.4.90
• 5.4.91
• 5.4.92
• 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

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

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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