Use of uninitialized resource in Linux kernel - CVE-2026-98929

Vulnerability details

The vulnerability allows a local privileged user to trigger a kernel warning and cause MACsec registration notifications to report uninitialized security attributes.

The vulnerability exists due to use of an uninitialized resource in the Linux kernel MACsec driver when network device registration generates notifications before the security entity (SecY) is initialized. A local privileged user can create a MACsec device to cause notifications to report uninitialized SecY attributes, including the secure channel identifier (SCI). Creating the device with MAC offload over an LRO-capable lower device while IPv4 forwarding is enabled by default also triggers a warning in rtmsg_ifinfo_build_skb(), because macsec_fill_info() encounters a zero key_len and returns -EMSGSIZE.

Affected software

How to mitigate CVE-2026-98929

External References

• https://git.kernel.org/stable/c/2b42adf3b8ee9a0e1d2629aca3c5a02a1c438066
• https://git.kernel.org/stable/c/b07bea42bf590edb0fd507ab25622a74af09548b
• https://git.kernel.org/stable/c/c2de369c5c5b8599ca10fd5ca8d11fcd845c1331

Related Security Bulletins

• Use of uninitialized resource in Linux kernel net driver
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more