{"id":"CVE-2026-64032","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: mcast: Fix a possible use-after-free when removing a bridge port\n\nWhen per-VLAN multicast snooping is enabled, the bridge iterates over\nall the bridge ports, di…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: mcast: Fix a possible use-after-free when removing a bridge port\n\nWhen per-VLAN multicast snooping is enabled, the bridge iterates over\nall the bridge ports, di…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.15.186, < 5.15.209","linux_kernel >= 6.1.142, < 6.1.175","linux_kernel >= 6.6.95, < 6.6.142","linux_kernel >= 6.12.35, < 6.12.92","linux_kernel >= 6.15.4, < 6.18.34","linux_kernel >= 6.19, < 7.0.11","linux_kernel = 7.1"],"patched":["linux_kernel 7.0.11"],"published":"2026-07-19","updated":"2026-10-13","sourceUpdated":"2026-10-13T15:32:51.113","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64032","references":[{"url":"https://git.kernel.org/stable/c/1900ca8acb92fbea8bf9abef9927c7fed03db7fc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4df78ff02629c7729168f0696a7a2123c389818d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7213256c91ed778a0997c2029c152b18dc50e4fd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a9224862d597d0eed0a34bbb27343f703fc4113f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ddefd1b8e5eb58933a697ab38334f0fd82e7fb8b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ebe5561154c823b323bd06e350b55e0b8604d851","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ed3b69e60385a03df11c6d12e5d7bdf0f4a11b70","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00171,"epssPercentile":0.0599,"ingestedAt":"2026-10-13T15:33:40.028Z","slug":"CVE-2026-64032","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbridge: mcast: Fix a possible use-after-free when removing a bridge port\n\nWhen per-VLAN multicast snooping is enabled, the bridge iterates over\nall the bridge ports, disables the per-port multicast context on each\nport and enables the per-{port, VLAN} multicast contexts instead. The\nreverse happens when per-VLAN multicast snooping is disabled.\n\nWhen global multicast snooping is enabled, the bridge iterates over all\nthe bridge ports and enables the per-port multicast context on each\nport. The reverse happens when multicast snooping is disabled.\n\nThe above scheme can result in a situation where both types of contexts\n(per-port and per-{port, VLAN}) are enabled on a single bridge port:\n\n # ip link add name br1 up type bridge mcast_snooping 1 mcast_querier 1 vlan_filtering 1\n # ip link add name dummy1 up master br1 type dummy\n # ip link set dev br1 type bridge mcast_vlan_snooping 1\n # ip link set dev br1 type bridge mcast_snooping 0\n # ip link set dev br1 type bridge mcast_snooping 1\n\nThis is not intended and it is a problem since the commit cited below.\nPrior to this commit, when removing a bridge port,\nbr_multicast_disable_port() would disable the per-port multicast context\nand the per-{port, VLAN} multicast contexts would get disabled when\nflushing VLANs.\n\nAfter this commit, br_multicast_disable_port() only disables the\nper-port multicast context if per-VLAN multicast snooping is disabled.\nIf both types of contexts were enabled on the port when it was removed,\nthe per-port multicast context would remain enabled when freeing the\nbridge port, leading to a use-after-free [1].\n\nFix by preventing the bridge from enabling / disabling the per-port\nmulticast contexts when toggling global multicast snooping if per-VLAN\nmulticast snooping is enabled.\n\n[1]\nODEBUG: free active (active state 0) object: ffff88810f8bda78 object type: timer_list hint: br_ip6_multicast_port_query_expired (net/bridge/br_multicast.c:1927)\nWARNING: lib/debugobjects.c:629 at debug_print_object+0x1b1/0x3e0, CPU#5: swapper/5/0\n[...]\nCall Trace:\n<IRQ>\n__debug_check_no_obj_freed (lib/debugobjects.c:1116)\nkfree (mm/slub.c:2620 mm/slub.c:6250 mm/slub.c:6565)\nkobject_cleanup (lib/kobject.c:689)\nrcu_do_batch (kernel/rcu/tree.c:2617)\nrcu_core (kernel/rcu/tree.c:2869)\nhandle_softirqs (kernel/softirq.c:622)\n__irq_exit_rcu (kernel/softirq.c:656 kernel/softirq.c:496 kernel/softirq.c:735)\nirq_exit_rcu (kernel/softirq.c:752)\nsysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1061 (discriminator 47) arch/x86/kernel/apic/apic.c:1061 (discriminator 47))\n</IRQ>\n\n## Affected\n\n- `linux_kernel >= 5.15.186, < 5.15.209`\n- `linux_kernel >= 6.1.142, < 6.1.175`\n- `linux_kernel >= 6.6.95, < 6.6.142`\n- `linux_kernel >= 6.12.35, < 6.12.92`\n- `linux_kernel >= 6.15.4, < 6.18.34`\n- `linux_kernel >= 6.19, < 7.0.11`\n- `linux_kernel = 7.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.11`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}