CVE-2026-74684: Linux

High severity, CVSS 7.1. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: net: tap: set skb->dev before parsing virtio net header in tap_get_user_xdp() The commit 4f61f133f354 ("net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is null") fixed a crash in tap_get_user() by assigning skb->dev before calling tun_vnet_hdr_to_skb(). This is required because virtio_net_hdr_to_skb() may invoke dev_parse_header_protocol(), which dereferences skb->dev. Without the assignment, a NULL pointer dereference can occur. However, tap_get_user_xdp() still parses the virtio-net header before assigning skb->dev. When the vhost TX path passes an XDP buffer containing a GSO virtio-net header but the protocol is set to zero on purpose, tun_vnet_hdr_to_skb() can reach dev_parse_header_protocol() while skb->dev is still NULL, resulting in a crash. Fix this by looking up the tap device and assigning skb->dev before calling tun_vnet_hdr_to_skb(), matching the ordering already used in tap_get_user(). Preserve the existing RCU read-side critical section across dev_queue_xmit().

Affected products

• Linux Linux: from 4.14.226, before 4.15 (fixed in 4.15); from 4.19.181, before 4.20 (fixed in 4.20); from 5.4.106, before 5.5 (fixed in 5.5); from 5.10.24, before 5.11 (fixed in 5.11); from 5.11.7, before 5.12 (fixed in 5.12); from 5.12, before 6.12.105 (fixed in 6.12.105); …

Published 2026-08-22. Last modified 2026-08-25.