Memory leak in Linux kernel - CVE-2026-74543

Vulnerability details

The vulnerability allows a local attacker to cause a denial of service.

The vulnerability exists due to a memory leak in udp_tunnel_nic_unregister() when handling failed device registration and netdevice unregister events. A local attacker can trigger device registration failure with queued work to cause a denial of service.

The issue occurs because a queued work item can cause the unregister path to return early, leaving a struct udp_tunnel_nic allocation permanently leaked.

Affected software

How to mitigate CVE-2026-74543

External References

• https://git.kernel.org/stable/c/080695e6f005e2396f1207fd69d24c442cb230c6
• https://git.kernel.org/stable/c/b322532a4b774db1b480a2de84125910a70739a5
• https://git.kernel.org/stable/c/b712da45bd9b9835d132e9fbc0c3e43c164cb1fd
• https://git.kernel.org/stable/c/f82a2ded3d7a9098267c84f14eafdb98c4550ac5

Related Security Bulletins

• Memory leak in Linux kernel ipv4
• Debian update for linux