{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74475", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.903Z", "datePublished": "2026-08-15T12:27:10.685Z", "dateUpdated": "2026-08-19T16:37:28.096Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:37:28.096Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/vxlan/vxlan_core.c" ], "versions": [ { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "32a9590a8d30426e3db63e6b20893e47e02576c0", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "d0993fc053f29e15cc7c9fe2029df3882a2ab5ab", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "87210054bad82bbae6f483a742dc45722fb47a6b", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "ec341bb76d77b4c2948764375ee6bfeef4bb41c3", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "ff89415d34c3ab9f5312316423122e664ed3524f", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "05f2987f73daa05333fd713d05546142f9f7c5f0", "status": "affected", "versionType": "git" }, { "version": "e4f67addf158f98f8197e08974966b18480dc751", "lessThan": "8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/vxlan/vxlan_core.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.151", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.103", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.44", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "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" } ] } ] } ], "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" } ], "title": "vxlan: use neigh_ha_snapshot() in route_shortcircuit()", "x_generator": { "engine": "bippy-1.2.0" } } } }