CVE-2026-74688 (GCVE-0-2026-74688)
Vulnerability from cvelistv5
Published
2026-08-22 15:32
Modified
2026-08-25 05:41
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sctp: clear control chunk transport if it is being removed
sctp_make_heartbeat_ack() caches the destination transport in
chunk->transport without taking a reference. When src_out_of_asoc_ok is
enabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead
of being transmitted immediately.
If the peer transport is removed while the chunk is still queued,
sctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing,
but only clears cached transport pointers in out_chunk_list. The queued
control chunk therefore retains a dangling transport pointer.
Once an ASCONF_ACK clears the suppression and the queued control chunk is
transmitted, SCTP dereferences the stale transport pointer, leading to a
use-after-free.
Fix this by also clearing chunk->transport for queued control chunks in
control_chunk_list when removing the transport.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef Version: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sctp/associola.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
},
{
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.1"
},
{
"lessThan": "3.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"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": "5.10.265",
"versionStartIncluding": "3.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.216",
"versionStartIncluding": "3.1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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{
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.45",
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},
{
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: clear control chunk transport if it is being removed\n\nsctp_make_heartbeat_ack() caches the destination transport in\nchunk-\u003etransport without taking a reference. When src_out_of_asoc_ok is\nenabled, the HEARTBEAT ACK may remain queued on control_chunk_list instead\nof being transmitted immediately.\n\nIf the peer transport is removed while the chunk is still queued,\nsctp_assoc_rm_peer() drops the transport and schedules it for RCU freeing,\nbut only clears cached transport pointers in out_chunk_list. The queued\ncontrol chunk therefore retains a dangling transport pointer.\n\nOnce an ASCONF_ACK clears the suppression and the queued control chunk is\ntransmitted, SCTP dereferences the stale transport pointer, leading to a\nuse-after-free.\n\nFix this by also clearing chunk-\u003etransport for queued control chunks in\ncontrol_chunk_list when removing the transport."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The bug is reached from remotely received SCTP packets (HEARTBEAT, ASCONF, ASCONF_ACK) processed in sctp_rcv() and the association input state machine on internet-facing SCTP servers and telecom endpoints.\nAC:L - A remote SCTP peer controls packet sequencing and can send HEARTBEAT while src_out_of_asoc_ok blocks transmission, remove transports via ASCONF DEL_IP, then trigger flush when ASCONF_ACK clears suppression.\nPR:N - Exploitation requires only a network-reachable established SCTP association; the attacker needs no Linux credentials, capabilities, or namespaces\u2014only the ability to send valid SCTP traffic to the target.\nUI:N - No victim user action is required; the use-after-free is triggered entirely by SCTP protocol messages sent by a remote peer during normal association operation or address migration.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the host kernel; it does not cross VM, container, or IOMMU security boundaries.\nC:H - Stale chunk-\u003etransport pointers dereference RCU-freed sctp_transport objects in sctp_outq_select_transport() and sctp_packet_transmit(), a use-after-free that enables arbitrary kernel memory disclosure via heap grooming.\nI:H - Use-after-free of sctp_transport allows controlled reuse of freed kmalloc objects, providing a standard path to arbitrary kernel writes and local privilege escalation or remote code execution in kernel context.\nA:H - Dereferencing the freed transport during control-chunk transmission can immediately kernel oops or panic the system; use-after-free bugs inherently threaten availability even when full exploitation is not attempted."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-25T05:41:32.712Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/dbb3f418a8665ffb0514e1a9520ab6a1c5d4d886"
},
{
"url": "https://git.kernel.org/stable/c/fad4766a74220fe579c6fcaa10ba01c23529814f"
},
{
"url": "https://git.kernel.org/stable/c/936658ec41c28c397ef390140e02d4c91ade92f0"
},
{
"url": "https://git.kernel.org/stable/c/8de65194a04d2552cd39b6c67d942d490f22d174"
},
{
"url": "https://git.kernel.org/stable/c/6160e756db81d6cb63e3e2952efcf6c5134be385"
},
{
"url": "https://git.kernel.org/stable/c/18d704bdd809377dfd81a3c2f42426763b5da227"
},
{
"url": "https://git.kernel.org/stable/c/4d6b9cac6df5e0cfef1a66b3edd7aebdb9e4b7e7"
},
{
"url": "https://git.kernel.org/stable/c/c9158ceaf27780ef64534ad72f44ffde3f8ccc49"
}
],
"title": "sctp: clear control chunk transport if it is being removed",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74688",
"datePublished": "2026-08-22T15:32:53.423Z",
"dateReserved": "2026-08-15T05:44:03.926Z",
"dateUpdated": "2026-08-25T05:41:32.712Z",
"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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