CVE-2026-74476 veth: convert frag_list skbs before running XDP
A flaw in the Linux kernel veth driver causes a crash when processing fragmented packets with XDP, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74476?
CVE-2026-74476 is a critical vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
veth: convert frag_list skbs before running XDP
A frag_list skb can reach veth with data_len set but nr_frags zero. veth_convert_skb_to_xdp_buff() only converts skbs that are shared, locked, have frags[], or do not have enough headroom. It later uses skb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and xdp_frags_size.
That exposes frag_list data to XDP as if it were stored in frags[], but frags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment metadata, walk an empty fragment entry, and crash in memcpy() from __xsk_rcv().
Route non-linear skbs through skb_pp_cow_data() before exposing them to XDP, and only advertise XDP frags when the resulting skb has frags[]. skb_copy_bits() already handles frag_list input, and skb_pp_cow_data() builds frags[] output with skb_add_rx_frag(), which is the representation XDP multi-buffer expects.
Which versions are affected by CVE-2026-74476?
How do I fix CVE-2026-74476?
Apply the vendor's patch.
Is CVE-2026-74476 being exploited?
There is no known exploitation of CVE-2026-74476 in the wild and no public exploit code.
Sources
Also known as AZL-96458, BELL-CVE-2026-74476, DEBIAN-CVE-2026-74476, GHSA-p72r-vmh2-4xj6, UBUNTU-CVE-2026-74476.