Linux Kernel up to 6.12.66/6.18.6/6.19-rc5 macvlan_forward_source use after free

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 6.12.66/6.18.6/6.19-rc5. Affected by this issue is the function macvlan_forward_source. The manipulation results in use after free. This vulnerability is identified as CVE-2026-23001. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.66/6.18.6/6.19-rc5. It has been classified as critical. Affected is the function macvlan_forward_source. 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. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: macvlan: fix possible UAF in macvlan_forward_source() Add RCU protection on (struct macvlan_source_entry)->vlan. Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts. This allows macvlan_forward_source() to skip over entries queued for freeing. Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)). https: //lore.kernel.org/netdev/[email protected]/T/#u

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-23001 since 01/13/2026. The exploitability is told to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 296537 (Linux Distros Unpatched Vulnerability : CVE-2026-23001), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.67, 6.18.7 or 6.19-rc6 eliminates this vulnerability. Applying the patch 8518712a2ca952d6da2238c6f0a16b4ae5ea3f13/6dbead9c7677186f22b7981dd085a0feec1f038e/7470a7a63dc162f07c26dbf960e41ee1e248d80e 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 databases at Tenable (296537), EUVD (EUVD-2026-4615) and CERT Bund (WID-SEC-2026-0215). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.19-rc1
• 6.19-rc2
• 6.19-rc3
• 6.19-rc4
• 6.19-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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