{"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"}}}}