{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74480", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.904Z", "datePublished": "2026-08-15T12:27:13.803Z", "dateUpdated": "2026-10-16T19:05:48.808Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:37:33.031Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: stop fast-leave after deleting a port group\n\nbr_multicast_leave_group() iterates mp->ports with pp = &p->next in\nits fast-leave path. After br_multicast_del_pg() removes p,\ncontinuing the loop advances pp through the deleted entry.\n\nIf multicast-to-unicast was enabled, the bridge can hold multiple port\ngroups for the same port and group with different source MAC\naddresses. Once multicast-to-unicast is disabled,\nbr_port_group_equal() matches those entries by port only. A fast leave\ncan then delete one entry and continue from its stale next pointer,\nleaving mp->ports pointing at a deleted port group.\n\nFast leave only needs to remove one matching port group. Break after\nbr_multicast_del_pg() so the loop stops before dereferencing the\nremoved entry." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The bug is reached when the bridge network stack processes attacker-supplied IGMP/MLD Leave packets received on a bridge port (br_handle_frame_finish -> br_multicast_rcv -> br_ip4/ip6_multicast_leave_group -> br_multicast_leave_group), requiring no local syscall access.\nAC:L - Once a bridge has IGMP snooping, fast-leave, and leftover duplicate port groups (common on WiFi APs that used multicast-to-unicast), an attacker can reliably trigger the bug by sending IGMP/MLD joins then a Leave; no uncontrollable race or rare timing is required.\nPR:N - No privileges or authentication are required on the target; any host on an attached bridge port can inject IGMP/MLD Leave packets that are processed and reach the vulnerable fast-leave deletion loop.\nUI:N - Exploitation requires only attacker-sent multicast control packets; no victim user action such as opening files, clicking links, or mounting filesystems is needed.\nS:U - Impact is kernel heap corruption and use-after-free within the bridge/multicast subsystem on the same host; it does not cross a VM/hypervisor or IOMMU security boundary by itself.\nC:H - Deleting a port group then continuing the list walk dereferences freed net_bridge_port_group memory and can leave mp->ports dangling, giving a use-after-free read primitive exploitable for arbitrary kernel memory disclosure.\nI:H - Corrupting the mp->ports linked list via stale next pointers after br_multicast_del_pg() enables attacker-influenced kernel heap corruption that can be developed into arbitrary write and privilege escalation.\nA:H - The use-after-free and corrupted multicast database pointers cause kernel oops/panics when subsequent bridge multicast forwarding or MDB operations traverse the broken port-group list, enabling repeatable denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bridge/br_multicast.c" ], "versions": [ { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "d6c32e2e25a9a06ba021030e26b6d602a277eb72", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "482bcb85139addb4e8ac8ed10baeda3e0aad4031", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "1a109cc9890d017c41d77e6c82da739579c49f0b", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "159ad90cb929c033308bb39a2c5f8fbf393b77aa", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "4695430e8132420bf8de94da3eb36a6cf35fde6b", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "0309ebbc570000ea0df11c06b69798e5860c5f6f", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4", "status": "affected", "versionType": "git" }, { "version": "6db6f0eae6052b70885562e1733896647ec1d807", "lessThan": "a39789f211b8a4125f0c70e05b30cf715f4f187d", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bridge/br_multicast.c" ], "versions": [ { "version": "4.11", "status": "affected" }, { "version": "0", "lessThan": "4.11", "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": "4.11", "versionEndExcluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.6.151" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.12.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.18.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "7.1.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d6c32e2e25a9a06ba021030e26b6d602a277eb72" }, { "url": "https://git.kernel.org/stable/c/482bcb85139addb4e8ac8ed10baeda3e0aad4031" }, { "url": "https://git.kernel.org/stable/c/1a109cc9890d017c41d77e6c82da739579c49f0b" }, { "url": "https://git.kernel.org/stable/c/159ad90cb929c033308bb39a2c5f8fbf393b77aa" }, { "url": "https://git.kernel.org/stable/c/4695430e8132420bf8de94da3eb36a6cf35fde6b" }, { "url": "https://git.kernel.org/stable/c/0309ebbc570000ea0df11c06b69798e5860c5f6f" }, { "url": "https://git.kernel.org/stable/c/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4" }, { "url": "https://git.kernel.org/stable/c/a39789f211b8a4125f0c70e05b30cf715f4f187d" } ], "title": "net: bridge: stop fast-leave after deleting a port group", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2026-74480", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "yes" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2026-10-16T18:57:40.918598Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:05:48.808Z" } } ] } }