{"id":"CVE-2026-98568","title":"vxlan: use one headroom snapshot for neighbour replies","summary":"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 headroo…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 45a67662bf8ce3aa5643accf98d328dfbb47eaf6","Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 315d42ca39f69846662961c25dcf2bb07c350d14","Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < a3c5eb6e382dd426a5e7eb08608897ed57167ff7","Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < ff022fd9d0f0282c575e11778b96bd1b637503eb","Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 481506a756dcd828ef42391cb08f38d8d96d38fc","Linux d8be18c52dbc94989f6d74637b731af39cd3d902","Linux 3927dace523706cc00f808520eaf2125dd7c07b5","Linux >= 3.12.18 < 3.13","Linux >= 3.13.10 < 3.14","Linux 3.14"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:18:34.562Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98568","references":[{"url":"https://git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6"},{"url":"https://git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14"},{"url":"https://git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7"},{"url":"https://git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb"},{"url":"https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.261Z","slug":"CVE-2026-98568","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 45a67662bf8ce3aa5643accf98d328dfbb47eaf6`\n- `Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 315d42ca39f69846662961c25dcf2bb07c350d14`\n- `Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < a3c5eb6e382dd426a5e7eb08608897ed57167ff7`\n- `Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < ff022fd9d0f0282c575e11778b96bd1b637503eb`\n- `Linux >= 4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa < 481506a756dcd828ef42391cb08f38d8d96d38fc`\n- `Linux d8be18c52dbc94989f6d74637b731af39cd3d902`\n- `Linux 3927dace523706cc00f808520eaf2125dd7c07b5`\n- `Linux >= 3.12.18 < 3.13`\n- `Linux >= 3.13.10 < 3.14`\n- `Linux 3.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}