{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64450", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.788Z", "datePublished": "2026-07-25T08:51:20.319Z", "dateUpdated": "2026-08-17T04:55:54.043Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:55:54.043Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/bcast.c", "net/tipc/bcast.h", "net/tipc/node.c" ], "versions": [ { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "055663d21dc4336f67933ab26bef3c5934be6324", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "016f5995c37a5a2c45198308f830f244517d70b7", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "74b45af86a767594ba52330cd440ea84e24d700d", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "9a51115fcdc78687c8852bf93a1db3951dbb223b", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "a21ed5064217cc33726da6c7ef1a520eba43aea1", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "2de42e268174766cb2e2b90721afdfdff70e0d8d", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "f333b6851bdf326fd2134133272dbbed0c94d921", "status": "affected", "versionType": "git" }, { "version": "d7626b5acff9227e2a65da636a53e09bdafdc0aa", "lessThan": "2b66974a1b6134a4bbc3bfed181f7418f688eb54", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/bcast.c", "net/tipc/bcast.h", "net/tipc/node.c" ], "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "lessThan": "5.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324" }, { "url": "https://git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7" }, { "url": "https://git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d" }, { "url": "https://git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b" }, { "url": "https://git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1" }, { "url": "https://git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d" }, { "url": "https://git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921" }, { "url": "https://git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54" } ], "title": "tipc: fix out-of-bounds read in broadcast Gap ACK blocks", "x_generator": { "engine": "bippy-1.2.0" } } } }