CVE-2026-74582

Status: UPDATED  |  Advisory ID: CVE-2026-74582

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

packet: use consistent hard_header_len in non-ring send paths

packet_snd() reads dev->hard_header_len multiple times while allocating

and constructing an skb. Device reconfiguration can change this value

concurrently, for example through bonding device type changes.

For SOCK_RAW, packet_snd() can save a larger value in reserve and later

allocate headroom using a smaller value. Moving skb->data back by reserve

then places it before skb->head, and the following copy from userspace can

attempt an out-of-bounds write.

packet_sendmsg_spkt() has the same issue because it calculates its

reservation and header offset from separate reads before dropping the RCU

read lock to allocate the skb.

Add LL_RESERVED_SPACE_EX() for callers that already saved a header length.

Read hard_header_len once in packet_snd() and use it for allocation and

construction. In packet_sendmsg_spkt(), preserve the allocation-time value

through the device lookup retry.

The separate SOCK_DGRAM consistency problem between hard_header_len and

header_ops->create is not addressed here. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References