{"id":"CVE-2026-98568","summary":"vxlan: use one headroom snapshot for neighbour replies","details":"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.","modified":"2026-10-19T02:45:27.828896196Z","published":"2026-10-18T15:18:34.562Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98568.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14"},{"type":"WEB","url":"https://git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98568.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98568"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa"},{"fixed":"45a67662bf8ce3aa5643accf98d328dfbb47eaf6"},{"fixed":"315d42ca39f69846662961c25dcf2bb07c350d14"},{"fixed":"a3c5eb6e382dd426a5e7eb08608897ed57167ff7"},{"fixed":"ff022fd9d0f0282c575e11778b96bd1b637503eb"},{"fixed":"481506a756dcd828ef42391cb08f38d8d96d38fc"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.12.18"},{"fixed":"3.13"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.13.10"},{"fixed":"3.14"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d8be18c52dbc94989f6d74637b731af39cd3d902"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3927dace523706cc00f808520eaf2125dd7c07b5"}]}],"versions":["v3.12.74","v3.12.73","v3.12.72","v3.12.71","v3.12.70","v3.12.69","v3.12.68","v3.12.67","v3.12.66","v3.12.65","v3.12.64","v3.12.63","v3.12.62","v3.12.61","v3.12.60","v3.12.59","v3.12.58","v3.12.57","v3.12.56","v3.12.55","v3.12.54","v3.12.53","v3.12.52","v3.12.51","v3.12.50","v3.12.49","v3.12.48","v3.12.47","v3.12.46","v3.12.45","v3.12.44","v3.12.43","v3.12.42","v3.12.41","v3.12.40","v3.12.39","v3.12.38","v3.12.37","v3.12.36","v3.12.35","v3.12.34","v3.12.33","v3.12.32","v3.12.31","v3.12.30","v3.12.29","v3.12.28","v3.12.27","v3.12.26","v3.12.25","v3.12.24","v3.12.23","v3.12.22","v3.12.21","v3.12.20","v3.12.19","v3.12.18","v3.13.11","v3.13.10"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98568.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.14.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98568.json"}}],"schema_version":"1.9.0"}