{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68116", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.369Z", "datePublished": "2026-08-10T11:58:34.612Z", "dateUpdated": "2026-08-17T04:59:06.287Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:59:06.287Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: mdb: Fix source list corruption on a failed replace\n\nWhen replacing the source list of an MDB remote entry, all existing\nsources are first marked for deletion and vxlan_mdb_remote_srcs_add()\nis then called to add the new source list. Sources present in the new\nlist have their deletion mark cleared, and any sources left marked\nafterwards are removed.\n\nIf vxlan_mdb_remote_srcs_add() fails partway through, its error path\ndeletes all entries on the remote's source list. That rollback is only\ncorrect for its other caller, vxlan_mdb_remote_add(), where the remote\nwas just allocated and the list contains solely entries added during\nthe call. On the replace path the list also holds pre-existing sources,\nso a failed replace tears them down together with their (S, G)\nforwarding entries instead of leaving the entry unchanged.\n\nThis is reachable from an existing (*, G) remote. An EXCLUDE filter\nthat loses sources starts forwarding traffic that should be blocked,\nwhile an INCLUDE filter that loses sources drops traffic that should be\nforwarded.\n\nMark entries created during the current pass with a new\nVXLAN_SGRP_F_NEW flag. On failure, delete only those entries and clear\nthe deletion mark on the pre-existing ones, so a failed replace leaves\nthe source list untouched. Retain the flag until the whole operation\nsucceeds and then clear it. Also stop vxlan_mdb_remote_src_add() from\ndeleting a pre-existing entry it only looked up when adding that\nentry's forwarding entry fails." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H", "baseScore": 7.9, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is only reachable via the RTM_NEWMDB rtnetlink control path (ndo_mdb_add); multicast data-plane packets use vxlan_mdb_xmit and never hit the replace/rollback logic.\nAC:L - An attacker with CAP_NET_ADMIN can create an existing (*,G) remote, issue NLM_F_REPLACE with a new source list, and reliably force vxlan_mdb_remote_srcs_add() to fail mid-loop (e.g., ENOMEM via memory pressure) to trigger the bad rollback.\nPR:L - rtnetlink requires CAP_NET_ADMIN for RTM_NEWMDB; this capability is obtainable by unprivileged users inside user/network namespaces, not solely by init-namespace root.\nUI:N - Exploitation requires only crafted rtnetlink MDB messages from a process with network-admin capability; no victim user action is needed.\nS:C - A corrupted EXCLUDE source list forwards multicast that policy intended to block to VXLAN remote peers, crossing intended overlay segmentation boundaries beyond the misconfigured netdev's local authority.\nC:L - EXCLUDE filter corruption removes per-source block rules, causing multicast payloads from previously blocked sources to be encapsulated and delivered to unauthorized VXLAN remotes.\nI:L - Failed replace corrupts MDB source lists and (S,G) forwarding state, causing unauthorized multicast delivery (EXCLUDE) or dropping traffic that should be forwarded (INCLUDE).\nA:H - INCLUDE filter corruption can wipe all source entries on a (*,G) remote, causing vxlan_mdb_xmit to permanently drop all multicast for that group until MDB state is manually repaired." } ] } ], "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_mdb.c" ], "versions": [ { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "lessThan": "5bc8fc1d2ff802eec839e03adef5df597421898d", "status": "affected", "versionType": "git" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "lessThan": "2c54dff57606590fa4abec46bab6bea3133f1539", "status": "affected", "versionType": "git" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "lessThan": "79370b573e92e8f190eb5f9a511fa5398340d8b2", "status": "affected", "versionType": "git" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "lessThan": "54a3c27b357dfb34f327f89bfadeb998bef8051e", "status": "affected", "versionType": "git" }, { "version": "a3a48de5eade770e911d35291217bdd69ce04ef1", "lessThan": "dcd9b465965422b9654f6026e8a2fa8984f74c3c", "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_mdb.c" ], "versions": [ { "version": "6.4", "status": "affected" }, { "version": "0", "lessThan": "6.4", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "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": "6.4", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5bc8fc1d2ff802eec839e03adef5df597421898d" }, { "url": "https://git.kernel.org/stable/c/2c54dff57606590fa4abec46bab6bea3133f1539" }, { "url": "https://git.kernel.org/stable/c/79370b573e92e8f190eb5f9a511fa5398340d8b2" }, { "url": "https://git.kernel.org/stable/c/54a3c27b357dfb34f327f89bfadeb998bef8051e" }, { "url": "https://git.kernel.org/stable/c/dcd9b465965422b9654f6026e8a2fa8984f74c3c" } ], "title": "vxlan: mdb: Fix source list corruption on a failed replace", "x_generator": { "engine": "bippy-1.2.0" } } } }