{"id":"CVE-2026-74480","title":"net: bridge: stop fast-leave after deleting a port group","summary":"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_de…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < d6c32e2e25a9a06ba021030e26b6d602a277eb72","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 482bcb85139addb4e8ac8ed10baeda3e0aad4031","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 1a109cc9890d017c41d77e6c82da739579c49f0b","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 159ad90cb929c033308bb39a2c5f8fbf393b77aa","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 4695430e8132420bf8de94da3eb36a6cf35fde6b","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 0309ebbc570000ea0df11c06b69798e5860c5f6f","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4","Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < a39789f211b8a4125f0c70e05b30cf715f4f187d","Linux 4.11"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:57:40.918598Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:05:48.808Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74480","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"}],"tags":["cve.org"],"epss":0.00579,"epssPercentile":0.4649,"ingestedAt":"2026-10-16T19:46:24.355Z","slug":"CVE-2026-74480","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < d6c32e2e25a9a06ba021030e26b6d602a277eb72`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 482bcb85139addb4e8ac8ed10baeda3e0aad4031`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 1a109cc9890d017c41d77e6c82da739579c49f0b`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 159ad90cb929c033308bb39a2c5f8fbf393b77aa`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 4695430e8132420bf8de94da3eb36a6cf35fde6b`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 0309ebbc570000ea0df11c06b69798e5860c5f6f`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < 4c57056ca6aace2e9f94ae9298bf49ef6b0c95e4`\n- `Linux >= 6db6f0eae6052b70885562e1733896647ec1d807 < a39789f211b8a4125f0c70e05b30cf715f4f187d`\n- `Linux 4.11`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}