CVE-2026-63991: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt() The skb_clone() function can return NULL if memory allocation fails. send_mcast_pkt() calls skb_clone() without checking the return value, which can lead to a NULL pointer dereference in send_pkt() when it dereferences skb->data. Add a NULL check after skb_clone() and skip the peer if the clone fails.

Affected products

• Linux Linux Kernel: from 3.14, before 5.10.259 (fixed in 5.10.259); from 5.11, before 5.15.210 (fixed in 5.15.210); from 5.16, before 6.1.176 (fixed in 6.1.176); from 6.2, before 6.6.143 (fixed in 6.6.143); from 6.7, before 6.12.93 (fixed in 6.12.93); from 6.13, before 6.18.35 (fixed in 6.18.35); …

Published 2026-07-19. Last modified 2026-10-07.