{"id":"CVE-2026-74475","state":"PUBLISHED","title":"vxlan: use neigh_ha_snapshot() in route_shortcircuit()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use neigh_ha_snapshot() in route_shortcircuit()\n\nThe neighbour hardware address n->ha can be updated asynchronously by the\nneighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without\nholding the seqlock loop can lead to torn reads or reading a partially updated\nMAC address.\n\nUse neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under\nread_seqbegin()/read_seqretry() lock protection before using it.\n\nNote that arp_reduce() and neigh_reduce() seem to have the same issue\nleft for future patches.","publishedAt":"2026-08-15T12:27:10.685Z","updatedAt":"2026-10-16T19:05:48.322Z","severity":{"score":10,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"32a9590a8d30426e3db63e6b20893e47e02576c0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"d0993fc053f29e15cc7c9fe2029df3882a2ab5ab","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"87210054bad82bbae6f483a742dc45722fb47a6b","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"ec341bb76d77b4c2948764375ee6bfeef4bb41c3","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"ff89415d34c3ab9f5312316423122e664ed3524f","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"05f2987f73daa05333fd713d05546142f9f7c5f0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d","versionType":"git"}],"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":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","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/32a9590a8d30426e3db63e6b20893e47e02576c0","https://git.kernel.org/stable/c/d0993fc053f29e15cc7c9fe2029df3882a2ab5ab","https://git.kernel.org/stable/c/87210054bad82bbae6f483a742dc45722fb47a6b","https://git.kernel.org/stable/c/d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0","https://git.kernel.org/stable/c/ec341bb76d77b4c2948764375ee6bfeef4bb41c3","https://git.kernel.org/stable/c/ff89415d34c3ab9f5312316423122e664ed3524f","https://git.kernel.org/stable/c/05f2987f73daa05333fd713d05546142f9f7c5f0","https://git.kernel.org/stable/c/8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74475.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74475","state":"PUBLISHED","datePublished":"2026-08-15T12:27:10.685Z","dateUpdated":"2026-10-16T19:05:48.322Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.903Z"},"containers":{"cna":{"title":"vxlan: use neigh_ha_snapshot() in route_shortcircuit()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use neigh_ha_snapshot() in route_shortcircuit()\n\nThe neighbour hardware address n->ha can be updated asynchronously by the\nneighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without\nholding the seqlock loop can lead to torn reads or reading a partially updated\nMAC address.\n\nUse neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under\nread_seqbegin()/read_seqretry() lock protection before using it.\n\nNote that arp_reduce() and neigh_reduce() seem to have the same issue\nleft for future patches."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"32a9590a8d30426e3db63e6b20893e47e02576c0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"d0993fc053f29e15cc7c9fe2029df3882a2ab5ab","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"87210054bad82bbae6f483a742dc45722fb47a6b","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"ec341bb76d77b4c2948764375ee6bfeef4bb41c3","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"ff89415d34c3ab9f5312316423122e664ed3524f","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"05f2987f73daa05333fd713d05546142f9f7c5f0","versionType":"git"},{"version":"e4f67addf158f98f8197e08974966b18480dc751","status":"affected","lessThan":"8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d","versionType":"git"}],"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":"3.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.8","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.151","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","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/32a9590a8d30426e3db63e6b20893e47e02576c0"},{"url":"https://git.kernel.org/stable/c/d0993fc053f29e15cc7c9fe2029df3882a2ab5ab"},{"url":"https://git.kernel.org/stable/c/87210054bad82bbae6f483a742dc45722fb47a6b"},{"url":"https://git.kernel.org/stable/c/d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0"},{"url":"https://git.kernel.org/stable/c/ec341bb76d77b4c2948764375ee6bfeef4bb41c3"},{"url":"https://git.kernel.org/stable/c/ff89415d34c3ab9f5312316423122e664ed3524f"},{"url":"https://git.kernel.org/stable/c/05f2987f73daa05333fd713d05546142f9f7c5f0"},{"url":"https://git.kernel.org/stable/c/8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","baseScore":10,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - route_shortcircuit() runs on the vxlan_xmit() transmit path when overlay IP/IPv6 traffic is encapsulated; in cloud/SDN VTEP deployments a remote tenant can drive dev_queue_xmit() through bridge/IP forwarding without any local syscall or netlink access.\nAC:L - The attacker controls both sides of the race by concurrently sending overlay traffic that hits route_shortcircuit() and generating neighbour ha updates (ARP/NDP churn); repeated attempts do not depend on victim state or uncontrollable memory layout.\nPR:N - Exploitation requires only the ability to send overlay/underlay packets to a VTEP that already has VXLAN_F_RSC and router FDB entries configured by infrastructure; no CAP_NET_ADMIN, root, or host credentials are needed on the victim.\nUI:N - Triggering is automatic during kernel packet forwarding and VXLAN encapsulation once matching traffic flows; no mount, file open, or other victim action is required beyond normal overlay operation.\nS:C - A torn n->ha read can rewrite the skb Ethernet destination and reselect a different FDB remote, mis-encapsulating traffic to an unintended VXLAN peer and crossing intended multi-tenant overlay segmentation boundaries beyond the local VTEP authority.\nC:H - Unsynchronized reads of neighbour ha during concurrent updates yield torn MAC values that drive post-rewrite FDB lookup and encapsulation, potentially delivering other tenants' overlay frames to an attacker-controlled remote endpoint or leaking mixed neighbour state.\nI:H - The corrupted hardware address is copied into the skb Ethernet header and steers subsequent vxlan_find_mac_tx()/vxlan_xmit_one() encapsulation, enabling deterministic overlay traffic redirection or injection toward an attacker-chosen VTEP rather than the intended router destination.\nA:L - While the host kernel does not panic, torn MAC rewriting can cause mis-encapsulation, FDB misses, and dropped or misdelivered overlay packets, producing intermittent connectivity loss and performance degradation on affected VTEP nodes under sustained attack."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:37:28.096Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74475","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:57:29.550730Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:05:48.322Z"}}]}}}