The Linux kernel's Open vSwitch stores flow actions as netlink attributes with a 16-bit length field (nla_len). A prior commit removed a length check that prevented nested action attributes from exceeding the maximum value of a u16, allowing oversized nested containers to be closed with truncated lengths. This causes later processing to interpret the action stream incorrectly, potentially leading to memory corruption or other impacts. The fix retains support for large total action streams but enforces rejection of nested containers that do not fit within the nla_len field, returning errors and ensuring proper resource cleanup.

The vulnerability can lead to structural inconsistencies in the Open vSwitch action stream, which may result in memory corruption or unintended behavior in the kernel networking stack. The CVSS vector indicates high impact on confidentiality, integrity, and availability, requiring local privileges with low attack complexity and no user interaction.

A fix has been implemented in the Linux kernel to reject oversized nested action attributes in Open vSwitch and properly handle resource cleanup on failure. Users should apply the official kernel update that includes this patch to remediate the vulnerability. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor advisory or Linux kernel mailing lists for the current remediation guidance.