{"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": "2026-08-19T16:37:33.031Z"}, "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"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/bridge/br_multicast.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d6c32e2e25a9a06ba021030e26b6d602a277eb72", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "482bcb85139addb4e8ac8ed10baeda3e0aad4031", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "1a109cc9890d017c41d77e6c82da739579c49f0b", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "159ad90cb929c033308bb39a2c5f8fbf393b77aa", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "4695430e8132420bf8de94da3eb36a6cf35fde6b", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "0309ebbc570000ea0df11c06b69798e5860c5f6f", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}, {"lessThan": "a39789f211b8a4125f0c70e05b30cf715f4f187d", "status": "affected", "version": "6db6f0eae6052b70885562e1733896647ec1d807", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/bridge/br_multicast.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.11"}, {"lessThan": "4.11", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.265", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.216", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.183", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.151", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.103", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.44", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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."}], "id": "CVE-2026-74480", "lastModified": "2026-08-19T17:21:05.127", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T13:17:52.820", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0309ebbc570000ea0df11c06b69798e5860c5f6f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/159ad90cb929c033308bb39a2c5f8fbf393b77aa"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1a109cc9890d017c41d77e6c82da739579c49f0b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4695430e8132420bf8de94da3eb36a6cf35fde6b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/482bcb85139addb4e8ac8ed10baeda3e0aad4031"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a39789f211b8a4125f0c70e05b30cf715f4f187d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d6c32e2e25a9a06ba021030e26b6d602a277eb72"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: net: bridge: stop fast-leave after deleting a port group", "id": "2517046", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2517046"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnet: bridge: stop fast-leave after deleting a port group\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.\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.\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.", "A flaw was found in the Linux kernel's network bridge module. When handling multicast fast-leave, a vulnerability exists where the system may attempt to access a port group after it has been deleted. This can occur if multicast-to-unicast was previously enabled and then disabled, leading to a stale pointer. This memory corruption vulnerability could lead to system instability or a denial of service."], "name": "CVE-2026-74480", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74480\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74480\nhttps://lore.kernel.org/linux-cve-announce/2026081536-CVE-2026-74480-e620@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[6db6f0eae6052b70885562e1733896647ec1d807,159ad90cb929c033308bb39a2c5f8fbf393b77aa)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[6db6f0eae6052b70885562e1733896647ec1d807,4695430e8132420bf8de94da3eb36a6cf35fde6b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[6db6f0eae6052b70885562e1733896647ec1d807,0309ebbc570000ea0df11c06b69798e5860c5f6f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[6db6f0eae6052b70885562e1733896647ec1d807,4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[6db6f0eae6052b70885562e1733896647ec1d807,a39789f211b8a4125f0c70e05b30cf715f4f187d)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.11"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,4.11)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.151,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.103,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.44,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.8,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-15T15:45:06.744955+00:00", "updated": "2026-08-21T23:45:03.444360+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}