{"id":"CVE-2026-98487","title":"net: bridge: mdb: restart port group walk after deletion","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mdb: restart port group walk after deletion\n\nbr_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking\nmp->ports. br_multicast_del_pg() can re-ent…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < 46ec55855c972504258c371677ac039ba20e5d12","Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe","Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < fe2a42789c12eb7c5d3a42191e2cc735a6c35ead","Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < ab1404ac81154a89fb61ac50ae9a04cd8d4834dc","Linux 6.8"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:16:04.746Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98487","references":[{"url":"https://git.kernel.org/stable/c/46ec55855c972504258c371677ac039ba20e5d12"},{"url":"https://git.kernel.org/stable/c/ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe"},{"url":"https://git.kernel.org/stable/c/fe2a42789c12eb7c5d3a42191e2cc735a6c35ead"},{"url":"https://git.kernel.org/stable/c/ab1404ac81154a89fb61ac50ae9a04cd8d4834dc"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.292Z","slug":"CVE-2026-98487","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mdb: restart port group walk after deletion\n\nbr_mdb_flush_pgs() keeps a pointer-to-pointer cursor while walking\nmp->ports. br_multicast_del_pg() can re-enter the same MDB entry through\nbr_multicast_sg_del_exclude_ports() and unlink other port groups. If the\ncursor points into one of those groups, the next iteration dereferences a\nstale cursor and can leave mp->ports pointing at freed memory.\n\nA following RTM_GETMDB exposes the dangling pointer:\n\n  BUG: KASAN: slab-use-after-free in br_mdb_dump\n  Read of size 8\n    br_mdb_dump\n    rtnl_mdb_dump\n    rtnl_dumpit\n    netlink_dump\n\nReset the cursor to mp->ports after every deletion. The deletion removes at\nleast the selected group, so the restarted walk always makes progress.\n\n## Affected\n\n- `Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < 46ec55855c972504258c371677ac039ba20e5d12`\n- `Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < ab3c4a4c85f2e1e8d04b5c1770dea8412d21c7fe`\n- `Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < fe2a42789c12eb7c5d3a42191e2cc735a6c35ead`\n- `Linux >= a6acb535afb2a3b688a7858f05b61f0433e480d5 < ab1404ac81154a89fb61ac50ae9a04cd8d4834dc`\n- `Linux 6.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}