{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-64450", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-64450" ], "published": "2026-07-25T08:51:45Z", "summary": "tipc: fix out-of-bounds read in broadcast Gap ACK blocks", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix out-of-bounds read in broadcast Gap ACK blocks\n\nA broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its\ndata area. tipc_get_gap_ack_blks() only verifies that the record's len\nfield is self-consistent with its ugack_cnt/bgack_cnt counts\n(sz == struct_size(p, gacks, ugack_cnt + bgack_cnt)); it does not check\nthat the record actually fits in the message data area, msg_data_sz().\n\nThe unicast caller tipc_link_proto_rcv() bounds it (\"if (glen > dlen)\nbreak;\"), but the broadcast caller tipc_bcast_sync_rcv() discards the\nreturned size, so tipc_link_advance_transmq() copies the record off the\nreceive skb with an attacker-controlled count:\n\n\tthis_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt),\n\t\t\t GFP_ATOMIC);\n\nA TIPC neighbour that negotiated TIPC_GAP_ACK_BLOCK triggers it with one\nordinary broadcast STATE_MSG (msg_bc_ack_invalid() clear), sized so its\ndata area is short, carrying a Gap ACK record with len = 0x400,\nbgack_cnt = 0xff and ugack_cnt = 0. len then equals\nstruct_size(p, gacks, 255), so the consistency check passes and ga is\nnon-NULL; kmemdup() reads struct_size(ga, gacks, 255) = 1024 bytes out\nof the much smaller skb:\n\n BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x48/0x60\n Read of size 1024 at addr ffff0000c7030d38 by task poc864/69\n Call trace:\n kmemdup_noprof+0x48/0x60\n tipc_link_advance_transmq+0x86c/0xb80\n tipc_link_bc_ack_rcv+0x19c/0x1e0\n tipc_bcast_sync_rcv+0x1c4/0x2c4\n tipc_rcv+0x85c/0x1340\n tipc_l2_rcv_msg+0xac/0x104\n The buggy address belongs to the object at ffff0000c7030d00\n which belongs to the cache skbuff_small_head of size 704\n The buggy address is located 56 bytes inside of\n allocated 704-byte region [ffff0000c7030d00, ffff0000c7030fc0)\n\nThe copied-out bytes are subsequently consumed as gap/ack values, but\nthe read is already out of bounds at the kmemdup() regardless of how\nthey are used.\n\nThe unicast STATE path drops such a message: \"if (glen > dlen) break;\"\nskips the rest of STATE_MSG handling and the skb is freed. Make the\nbroadcast path drop it too. tipc_bcast_sync_rcv() now bounds the record\nagainst msg_data_sz() and, when it does not fit, reports it back through\ntipc_node_bc_sync_rcv() to tipc_rcv() so the skb is discarded rather than\nprocessed. ga is not cleared on this path: ga == NULL already means\n\"legacy peer without Selective ACK\", a distinct legitimate state.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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": "6.1.178", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-64450" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-17T05:24:08Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 9.1, "cvss_v3_severity": "Critical", "scenario": "AV:N - TIPC packets can arrive through an IP/UDP bearer from a routable remote source, and the receive callback does not restrict packets to configured remote addresses. An attacker can also establish or spoof the required TIPC neighbour state without credentials.\nAC:L - The attacker controls capability advertisement, link establishment, broadcast synchronization, and the malformed STATE message; one packet then reliably performs the out-of-bounds copy without a race or uncontrollable condition.\nPR:N - The packet-receive path performs no capability or user-credential check, and TIPC discovery and link negotiation are unauthenticated when optional cryptographic keys are not configured. The vulnerable broadcast processing also precedes normal STATE-session validation.\nUI:N - No victim action is required after the TIPC bearer is active; receipt of the crafted STATE message directly invokes the vulnerable code.\nS:U - The vulnerability compromises availability and potentially confidentiality within the receiving kernel's existing security authority, without crossing a VM, IOMMU, or comparable scope boundary.\nC:H - The attacker-controlled count makes the kernel copy up to 1,024 bytes from a much smaller skb, incorporating substantial adjacent slab contents rather than a strictly bounded few-byte read.\nI:N - The defect performs an out-of-bounds read into a correctly sized new allocation; investigation found no out-of-bounds write, arbitrary-write primitive, or control-flow corruption.\nA:H - The demonstrated 1,024-byte slab-out-of-bounds access produces a KASAN BUG and can panic or fault hardened kernels, and an unauthenticated attacker can trigger it repeatedly." } } }