CVE-2026-63993

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.

References

• https://git.kernel.org/stable/c/5303925e360527243b46a440a04667826bbc72b7
• https://git.kernel.org/stable/c/609e63312c29aad18026a1d3222e123d4b6b0feb
• https://git.kernel.org/stable/c/6b8bfce9d2f774d2c2243e0248e03efb99bba6c0
• https://git.kernel.org/stable/c/7d9ef0cb271555d8cf39fefe6c981e1493b25ecf
• https://git.kernel.org/stable/c/8d435d68d71fb875876b722f4136caf74f2f48bd