Security Advisory
CVE-2026-63993
9.8
CRITICAL
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
skb_tunnel_check_pmtu() can change skb->head.
Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF.
Use instead ip_hdr(skb) as done in drivers/net/bareudp.c
and drivers/net/geneve.c.
Found by Sashiko.
Published Date
July 19, 2026
Official Source
NIST NVD Advisory