CVE-2026-53362 in Linux kernel IPv6: memory corruption

CVE-2026-53362 is a memory corruption vulnerability in the Linux kernel, specifically in __ip6_append_data(), the function handling data allocation for IPv6. An unprivileged user can trigger the flaw via UDPv6 sockets by combining MSG_MORE and MSG_SPLICE_PAGES, causing data to be copied beyond memory boundaries (past skb->end). The allocation error occurs in the paged path when fragheaderlen and transhdrlen cause undersizing of linear memory.

CVSS 7.8 (HIGH): the impact is significant because memory corruption can lead to denial of service or privilege escalation. The flaw was introduced by commit 773ba4fe9104 but became actively triggerable from commit ce650a166335. GitHub signals emerged on November 7, 2026, suggesting active interest from the research community. The patch status is confirmed in the official NVD description.

System administrators must apply kernel patches correcting the allocation in __ip6_append_data(). The fix adds fraggap to alloclen and subtracts it from pagedlen, restoring correct accounting. Verify kernel versions using uname -r and consult your distributor's repository (Red Hat, Ubuntu, Debian) for specific patches and release dates. Meanwhile, monitor UDPv6 traffic with MSG_SPLICE_PAGES on critical network applications.