{"api_version":"1","generated_at":"2026-08-02T01:11:16+00:00","cve":"CVE-2026-64450","urls":{"html":"https://cve.report/CVE-2026-64450","api":"https://cve.report/api/cve/CVE-2026-64450.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64450","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64450"},"summary":{"title":"tipc: fix out-of-bounds read in broadcast Gap ACK blocks","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:29","updated_at":"2026-07-27 05:16:51"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.1","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","data":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324","name":"https://git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d","name":"https://git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b","name":"https://git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1","name":"https://git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d","name":"https://git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7","name":"https://git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54","name":"https://git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921","name":"https://git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64450","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64450","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7626b5acff9227e2a65da636a53e09bdafdc0aa 055663d21dc4336f67933ab26bef3c5934be6324 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7626b5acff9227e2a65da636a53e09bdafdc0aa 016f5995c37a5a2c45198308f830f244517d70b7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7626b5acff9227e2a65da636a53e09bdafdc0aa 74b45af86a767594ba52330cd440ea84e24d700d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d7626b5acff9227e2a65da636a53e09bdafdc0aa 9a51115fcdc78687c8852bf93a1db3951dbb223b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64450","cve":"CVE-2026-64450","epss":"0.005370000","percentile":"0.421110000","score_date":"2026-07-29","updated_at":"2026-07-30 00:09:16"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/tipc/bcast.c","net/tipc/bcast.h","net/tipc/node.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"055663d21dc4336f67933ab26bef3c5934be6324","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"016f5995c37a5a2c45198308f830f244517d70b7","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"74b45af86a767594ba52330cd440ea84e24d700d","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"9a51115fcdc78687c8852bf93a1db3951dbb223b","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"a21ed5064217cc33726da6c7ef1a520eba43aea1","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"2de42e268174766cb2e2b90721afdfdff70e0d8d","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"f333b6851bdf326fd2134133272dbbed0c94d921","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"},{"lessThan":"2b66974a1b6134a4bbc3bfed181f7418f688eb54","status":"affected","version":"d7626b5acff9227e2a65da636a53e09bdafdc0aa","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/tipc/bcast.c","net/tipc/bcast.h","net/tipc/node.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.8"},{"lessThan":"5.8","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.261","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.261","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"5.8","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc2","versionStartIncluding":"5.8","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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":{"baseScore":9.1,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T05:01:12.346Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64450","datePublished":"2026-07-25T08:51:20.319Z","dateReserved":"2026-07-19T15:36:31.788Z","dateUpdated":"2026-07-27T05:01:12.346Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:29","lastModifiedDate":"2026-07-27 05:16:51","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64450","Ordinal":"1","Title":"tipc: fix out-of-bounds read in broadcast Gap ACK blocks","CVE":"CVE-2026-64450","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64450","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"tipc: fix out-of-bounds read in broadcast Gap ACK blocks"}]}}}