{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74282", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.880Z", "datePublished": "2026-08-15T05:57:52.048Z", "dateUpdated": "2026-08-17T05:45:23.387Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:45:23.387Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: prevent snt_unacked underflow on CONN_ACK\n\ntipc_sk_conn_proto_rcv() subtracts the peer-supplied connection ack count\nfrom the unsigned 16-bit send counter snt_unacked without checking that it\ndoes not exceed the number of messages actually outstanding:\n\n\ttsk->snt_unacked -= msg_conn_ack(hdr);\n\nmsg_conn_ack() is read straight from a received CONN_MANAGER/CONN_ACK\nmessage. If the ack count is larger than snt_unacked, the subtraction\nwraps to a near-maximum value, leaving tsk_conn_cong() permanently true\nand starving the connection of further transmits.\n\nValidate the ACK count at the start of the CONN_ACK block and drop the\nmessage if it acknowledges more messages than are outstanding. A peer (or,\nfor a local connection, the connected peer socket) can otherwise wedge a\nTIPC connection's send side by sending an oversized connection ack." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The flaw is reached when tipc_rcv() processes a remote CONN_MANAGER/CONN_ACK skb from a TIPC bearer (UDP port 6118 or Ethernet), traversing tipc_link_rcv()→tipc_sk_rcv()→tipc_sk_proto_rcv()→tipc_sk_conn_proto_rcv() with attacker-controlled ack count.\nAC:L - After a normal TIPC connect handshake, the connected peer can send a single CONN_ACK whose msg_conn_ack() exceeds snt_unacked; no races, timing, or rare layout conditions are needed and the malicious field is fully attacker-controlled.\nPR:N - Exploitation only requires becoming the established TIPC peer via a standard AF_TIPC connect/listen handshake; socket creation needs no capabilities and the protocol has no authentication gate before CONN_ACK processing.\nUI:N - No victim user action is required beyond the service already accepting TIPC connections; the attacker triggers the bug by sending one crafted CONN_ACK on the established connection.\nS:U - Impact is limited to corrupting flow-control state on a victim TIPC socket within the same kernel/host security boundary; there is no VM escape, container breakout, or IOMMU boundary crossing.\nC:N - The unsigned 16-bit underflow only corrupts the snt_unacked congestion counter and does not read or disclose kernel memory, pointers, or other sensitive information.\nI:N - The bug modifies only an internal send-window counter to block transmits and provides no arbitrary write, code execution, or user/kernel data modification primitive.\nA:H - An oversized CONN_ACK wraps snt_unacked to a near-maximum value, leaving tsk_conn_cong() permanently true and indefinitely starving the victim socket's transmit path until the connection is torn down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tipc/socket.c" ], "versions": [ { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "3388145d258cf2c4c98278e3987296007d30672e", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "67e55b054bf8025658dc0e255057f2a6236416bd", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "96f91b8ae1a489b3eca137e7acf42cf985fb8939", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "47ed873e4ceda34098bd46d8e96b4bb13cad3a04", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "b44bebdd32c9ff66ee2aebfc317ced44bedd9335", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "3cfa3d8e0dc167850edeb5bf5a07757db83fd54e", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "1e2c956745777e6ffdee7f30da5935741c03ee1e", "status": "affected", "versionType": "git" }, { "version": "10724cc7bb7832b482df049c20fd824d928c5eaa", "lessThan": "ab3e10b44ba5411779aac7afd2477917dd77750f", "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/socket.c" ], "versions": [ { "version": "4.7", "status": "affected" }, { "version": "0", "lessThan": "4.7", "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": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "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": "4.7", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.7", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3388145d258cf2c4c98278e3987296007d30672e" }, { "url": "https://git.kernel.org/stable/c/67e55b054bf8025658dc0e255057f2a6236416bd" }, { "url": "https://git.kernel.org/stable/c/96f91b8ae1a489b3eca137e7acf42cf985fb8939" }, { "url": "https://git.kernel.org/stable/c/47ed873e4ceda34098bd46d8e96b4bb13cad3a04" }, { "url": "https://git.kernel.org/stable/c/b44bebdd32c9ff66ee2aebfc317ced44bedd9335" }, { "url": "https://git.kernel.org/stable/c/3cfa3d8e0dc167850edeb5bf5a07757db83fd54e" }, { "url": "https://git.kernel.org/stable/c/1e2c956745777e6ffdee7f30da5935741c03ee1e" }, { "url": "https://git.kernel.org/stable/c/ab3e10b44ba5411779aac7afd2477917dd77750f" } ], "title": "tipc: prevent snt_unacked underflow on CONN_ACK", "x_generator": { "engine": "bippy-1.2.0" } } } }