{"id":"CVE-2026-98568","published":"2026-10-18T16:17:09.000","lastModified":"2026-10-19T10:19:14.750","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use one headroom snapshot for neighbour replies\n\nvxlan_na_create() samples LL_RESERVED_SPACE() to size the reply skb and then\nsamples it again to reserve headroom. A concurrent vxlan_changelink() can\nupdate needed_headroom between the two reads, creating a TOCTOU race. The\nsecond value can exceed the allocation and make the Ethernet header write out\nof bounds.\n\nThe race is reproducible on the unpatched kernel. It occurred when\nvxlan_na_create() generated a neighbour reply while vxlan_changelink() changed\nthe link headroom. KASAN caught a four-byte write two bytes beyond a 704-byte\nskbuff_small_head allocation.\n\nSnapshot the headroom once and use that value for both allocation and\nreservation.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14","tags":[]},{"url":"https://git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6","tags":[]},{"url":"https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc","tags":[]},{"url":"https://git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7","tags":[]},{"url":"https://git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}