CVE-2026-74282 (GCVE-0-2026-74282)
Vulnerability from cvelistv5
Published
2026-08-15 05:57
Modified
2026-08-17 05:45
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
tipc: prevent snt_unacked underflow on CONN_ACK
tipc_sk_conn_proto_rcv() subtracts the peer-supplied connection ack count
from the unsigned 16-bit send counter snt_unacked without checking that it
does not exceed the number of messages actually outstanding:
tsk->snt_unacked -= msg_conn_ack(hdr);
msg_conn_ack() is read straight from a received CONN_MANAGER/CONN_ACK
message. If the ack count is larger than snt_unacked, the subtraction
wraps to a near-maximum value, leaving tsk_conn_cong() permanently true
and starving the connection of further transmits.
Validate the ACK count at the start of the CONN_ACK block and drop the
message if it acknowledges more messages than are outstanding. A peer (or,
for a local connection, the connected peer socket) can otherwise wedge a
TIPC connection's send side by sending an oversized connection ack.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa Version: 10724cc7bb7832b482df049c20fd824d928c5eaa |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/tipc/socket.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "10724cc7bb7832b482df049c20fd824d928c5eaa",
"versionType": "git"
},
{
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]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/tipc/socket.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.7"
},
{
"lessThan": "4.7",
"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": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.261",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "4.7",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "4.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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-\u003esnt_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\u0027s send side by sending an oversized connection ack."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"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()\u2192tipc_sk_rcv()\u2192tipc_sk_proto_rcv()\u2192tipc_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\u0027s transmit path until the connection is torn down."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:45:23.387Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74282",
"datePublished": "2026-08-15T05:57:52.048Z",
"dateReserved": "2026-08-15T05:44:03.880Z",
"dateUpdated": "2026-08-17T05:45:23.387Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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