{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-99246", "modified": "2026-11-04T05:30:01Z", "upstream": [ "CVE-2026-99246" ], "published": "2026-11-03T11:19:11Z", "summary": "tipc: protect node reset trace dump with node lock", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: protect node reset trace dump with node lock\n\nThe tipc_node_reset_links trace event asks tipc_node_dump() to walk the\nnode's link entries. Unlike the other node events that request link data,\nthis event runs without the node lock.\n\nThis permits bearer teardown to free a link while the trace callback is\ndumping it:\n\n CPU 0 CPU 1\n trace_tipc_node_reset_links()\n tipc_node_dump()\n l = n->links[0].link\n tipc_node_write_lock()\n kfree(l)\n n->links[0].link = NULL\n tipc_node_write_unlock()\n tipc_link_dump(l)\n\ntipc_link_dump() then dereferences the stale pointer. KASAN reported:\n\n BUG: KASAN: slab-use-after-free in tipc_link_dump\n Read of size 4 by task poc/115\n Call Trace:\n tipc_link_dump+0x10cb/0x16b0\n tipc_node_dump+0x4bb/0x740\n trace_event_raw_event_tipc_node_class+0x258/0x360\n tipc_node_reset_links+0x14d/0x1a0\n tipc_rcv+0x13f5/0x3030\n tipc_udp_recv+0x4e3/0x670\n Allocated by task 0:\n tipc_link_create+0x1e1/0x1020\n tipc_node_check_dest+0x7d2/0x11a0\n tipc_disc_rcv+0xdbf/0x1430\n Freed by task 89:\n kfree+0x131/0x3c0\n tipc_node_link_down+0x267/0x4b0\n tipc_node_delete_links+0xec/0x160\n bearer_disable+0x107/0x260\n\nTake the node write lock around the trace event. This serializes the\ndump against tipc_node_link_down(delete=true), which frees the link\nunder the same write lock.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.191", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-99246" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c8b72ca0918e95f708f67c8b3e69b05290f2b6d2" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6e492cb98ca69cc1145175e23e22e3b84da7f26d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/7bb6a35bd6d69019539d8782fb590fd2aa8a3236" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/6abd93d01b0f495f29201925a5ee8e6a583c4044" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/a6101d62ccfa153db8c218ce59362b8e0316fd4f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b8b7d28dc2b7472ffd1eff3954c38f1976b21a7b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/fa8c78c0e49aa11fae116fd841e41aa8f2d68751" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/dddf197f29ba5e47a476dde82bf542ca2e0d5e5e" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-11-03T19:14:48Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.1, "cvss_v3_severity": "High", "scenario": "AV:N - A TIPC-over-UDP datagram (default port 6118) is received by tipc_udp_recv() and handed to tipc_rcv(); a non-sequential broadcast skb takes tipc_node_bc_rcv() and a LINK_PROTOCOL skb takes tipc_node_bc_sync_rcv(), both calling tipc_node_reset_links() on TIPC_LINK_DOWN_EVT. CONFIG_TIPC_MEDIA_UDP defaults to y, so the trigger is a routable IP packet.\nAC:H - The UAF is the lockless trace_tipc_node_reset_links() dump in tipc_node_reset_links() racing kfree of n->links[].link in tipc_node_link_down(delete=true). That delete=true path is only tipc_node_delete_links() from bearer_disable()/tipc_reset_bearer(), which a remote UDP peer cannot invoke, and the dump runs only if the tipc_node_reset_links tracepoint is already enabled.\nPR:N - tipc_disc_rcv() accepts LINK_CONFIG discovery from any UDP source whose net_id matches (default 4711) with no credentials; TIPC_CRYPTO keys are optional. After tipc_node_check_dest() creates the node/link, that same unauthenticated peer\u2019s broadcast or LINK_PROTOCOL packets reach tipc_node_reset_links().\nUI:N - Once a TIPC UDP bearer is already enabled, tipc_udp_recv() processes the attacker\u2019s packets in softirq; no victim mount, click, or other interactive step is required at exploit time.\nS:U - The use-after-free is of a host-kernel tipc_link object inside tipc_node_dump()/tipc_link_dump(); impact stays in the same kernel security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - KASAN reported a 4-byte read of a freed tipc_link in tipc_link_dump() from the stale n->links[0].link loaded by tipc_node_dump(); reclaiming that kmalloc object lets the dump read leftover or attacker-sprayed heap, including skb_peek() of transmq/deferdq heads.\nI:H - After bearer_disable() kfree()s the tipc_link, the stale pointer in tipc_node_dump() is a slab UAF: spraying a replacement object lets tipc_link_dump() follow attacker-chosen list pointers via skb_peek(), which is an exploitable kernel write/control-flow primitive.\nA:H - tipc_link_dump() dereference of the freed tipc_link oopses the kernel, matching the reported KASAN slab-use-after-free in the tipc_rcv() path; each overlapping packet and bearer teardown can repeat the crash." } } }