CVE-2026-74694

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

net/ncsi: fix heap OOB read in NCSI_CMD_SEND_CMD payload length

ncsi_send_cmd_nl() takes the number of bytes to copy from the

attacker-controlled ncsi_pkt_hdr.length field of the in-band packet

header, while the source buffer is the NCSI_ATTR_DATA netlink

attribute whose readable size is nla_len() - sizeof(ncsi_pkt_hdr).

The two length sources are never cross-checked: only

nla_len() >= sizeof(struct ncsi_pkt_hdr) is enforced.

With hdr->length set larger than the attribute payload (up to 65535

against at most 2032 readable bytes), ncsi_cmd_handler_oem() copies

past the end of the netlink attribute buffer with unsafe_memcpy(),

leaking up to ~64KB of kernel heap memory into the transmitted NCSI

command packet. The destination skb is sized by the declared payload,

so the write side does not overflow - this is a pure OOB read /

information leak, reachable with CAP_NET_ADMIN on systems with a

registered NCSI device (e.g.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References