{"id":"CVE-2026-98568","state":"PUBLISHED","title":"vxlan: use one headroom snapshot for neighbour replies","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.","publishedAt":"2026-10-18T15:18:34.562Z","updatedAt":"2026-10-30T12:38:26.027Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"e3e24f4c434c56952412f875b834aa9daaa4fb15","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"fcaf456092dc86fd5b0b523ac27ec0d114066931","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"45a67662bf8ce3aa5643accf98d328dfbb47eaf6","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"315d42ca39f69846662961c25dcf2bb07c350d14","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"a3c5eb6e382dd426a5e7eb08608897ed57167ff7","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"ff022fd9d0f0282c575e11778b96bd1b637503eb","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"481506a756dcd828ef42391cb08f38d8d96d38fc","versionType":"git"},{"version":"d8be18c52dbc94989f6d74637b731af39cd3d902","status":"affected","versionType":"git"},{"version":"3927dace523706cc00f808520eaf2125dd7c07b5","status":"affected","versionType":"git"},{"version":"3.12.18","status":"affected","lessThan":"3.13","versionType":"semver"},{"version":"3.13.10","status":"affected","lessThan":"3.14","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/vxlan/vxlan_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.14","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/vxlan/vxlan_core.c"]}],"references":["https://git.kernel.org/stable/c/e3e24f4c434c56952412f875b834aa9daaa4fb15","https://git.kernel.org/stable/c/9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1","https://git.kernel.org/stable/c/fcaf456092dc86fd5b0b523ac27ec0d114066931","https://git.kernel.org/stable/c/45a67662bf8ce3aa5643accf98d328dfbb47eaf6","https://git.kernel.org/stable/c/315d42ca39f69846662961c25dcf2bb07c350d14","https://git.kernel.org/stable/c/a3c5eb6e382dd426a5e7eb08608897ed57167ff7","https://git.kernel.org/stable/c/ff022fd9d0f0282c575e11778b96bd1b637503eb","https://git.kernel.org/stable/c/481506a756dcd828ef42391cb08f38d8d96d38fc"],"weaknesses":[],"ingestedAt":"2026-10-30T12:58:04.520Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98568.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98568","state":"PUBLISHED","datePublished":"2026-10-18T15:18:34.562Z","dateUpdated":"2026-10-30T12:38:26.027Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.357Z"},"containers":{"cna":{"title":"vxlan: use one headroom snapshot for neighbour replies","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"e3e24f4c434c56952412f875b834aa9daaa4fb15","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"fcaf456092dc86fd5b0b523ac27ec0d114066931","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"45a67662bf8ce3aa5643accf98d328dfbb47eaf6","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"315d42ca39f69846662961c25dcf2bb07c350d14","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"a3c5eb6e382dd426a5e7eb08608897ed57167ff7","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"ff022fd9d0f0282c575e11778b96bd1b637503eb","versionType":"git"},{"version":"4b29dba9c085a4fb79058fb1c45a2f6257ca3dfa","status":"affected","lessThan":"481506a756dcd828ef42391cb08f38d8d96d38fc","versionType":"git"},{"version":"d8be18c52dbc94989f6d74637b731af39cd3d902","status":"affected","versionType":"git"},{"version":"3927dace523706cc00f808520eaf2125dd7c07b5","status":"affected","versionType":"git"},{"version":"3.12.18","status":"affected","lessThan":"3.13","versionType":"semver"},{"version":"3.13.10","status":"affected","lessThan":"3.14","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/vxlan/vxlan_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.14","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/vxlan/vxlan_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e3e24f4c434c56952412f875b834aa9daaa4fb15"},{"url":"https://git.kernel.org/stable/c/9ed5a548b42d46e6968a46b67ca8a8e49b12a5a1"},{"url":"https://git.kernel.org/stable/c/fcaf456092dc86fd5b0b523ac27ec0d114066931"},{"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:38:26.027Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12.18"},{"vulnerable":true,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