CVE-2026-74588 (GCVE-0-2026-74588)
Vulnerability from cvelistv5
Published
2026-08-22 15:31
Modified
2026-08-25 05:40
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sctp: keep chunk->transport in step with the list it is queued on
__sctp_outq_flush_rtx() moves a gap-acked chunk onto another transport's
transmitted list without updating chunk->transport:
if (chunk->tsn_gap_acked) {
list_move_tail(&chunk->transmitted_list,
&transport->transmitted);
continue;
}
The chunk then sits on a live transport's list while chunk->transport still
names a different one. If that transport is removed - sctp_assoc_rm_peer()
from an ASCONF Delete-IP - sctp_transport_free() RCU-frees it and the chunk
is left with a dangling pointer. sctp_assoc_rm_peer() scrubs
peer->transmitted and asoc->outqueue.out_chunk_list, but the chunk is on
neither.
The pointer is not followed while tsn_gap_acked is set. A SACK that
reneges on the TSN clears the flag, and the next SACK reaches
tchunk->transport->flight_size -= sctp_data_size(tchunk);
inside the freed transport. KASAN reports a slab-use-after-free read in
sctp_check_transmitted(), freed from sctp_assoc_rm_peer(). Both the
removal and the SACKs come from the association peer.
Set chunk->transport at the move. The ordinary resend path needs nothing:
it reaches its list_move_tail() only after sctp_packet_append_chunk()
returned SCTP_XMIT_OK, and __sctp_packet_append_chunk() has rebound the
chunk by then.
Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sctp/outqueue.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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{
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}
]
},
{
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"product": "Linux",
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],
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"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.12"
},
{
"lessThan": "2.6.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"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": [
{
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"vulnerable": true
},
{
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},
{
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{
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},
{
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}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: keep chunk-\u003etransport in step with the list it is queued on\n\n__sctp_outq_flush_rtx() moves a gap-acked chunk onto another transport\u0027s\ntransmitted list without updating chunk-\u003etransport:\n\n\tif (chunk-\u003etsn_gap_acked) {\n\t\tlist_move_tail(\u0026chunk-\u003etransmitted_list,\n\t\t\t \u0026transport-\u003etransmitted);\n\t\tcontinue;\n\t}\n\nThe chunk then sits on a live transport\u0027s list while chunk-\u003etransport still\nnames a different one. If that transport is removed - sctp_assoc_rm_peer()\nfrom an ASCONF Delete-IP - sctp_transport_free() RCU-frees it and the chunk\nis left with a dangling pointer. sctp_assoc_rm_peer() scrubs\npeer-\u003etransmitted and asoc-\u003eoutqueue.out_chunk_list, but the chunk is on\nneither.\n\nThe pointer is not followed while tsn_gap_acked is set. A SACK that\nreneges on the TSN clears the flag, and the next SACK reaches\n\n\ttchunk-\u003etransport-\u003eflight_size -= sctp_data_size(tchunk);\n\ninside the freed transport. KASAN reports a slab-use-after-free read in\nsctp_check_transmitted(), freed from sctp_assoc_rm_peer(). Both the\nremoval and the SACKs come from the association peer.\n\nSet chunk-\u003etransport at the move. The ordinary resend path needs nothing:\nit reaches its list_move_tail() only after sctp_packet_append_chunk()\nreturned SCTP_XMIT_OK, and __sctp_packet_append_chunk() has rebound the\nchunk by then.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e"
}
],
"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 when the kernel SCTP stack processes inbound SACK and ASCONF chunks from a remote association peer via sctp_rcv()/sctp_inq_push(), with no local syscall or ioctl required on the victim.\nAC:L - The remote peer controls the SCTP protocol sequence (gap SACKs, ADDIP multihoming, ASCONF Delete-IP, and SACK reneging) needed to strand a chunk and free its transport; no attacker-uncontrollable race or rare memory layout is required.\nPR:N - Exploitation requires only network access as an established SCTP association peer sending authenticated protocol traffic; no local Linux account, capability, or namespace privilege is needed on the victim host.\nUI:N - No victim user action is required beyond normal automated SCTP server/client operation; the attacker drives the entire trigger sequence with crafted SACK and ASCONF packets on the existing association.\nS:U - Impact is confined to kernel memory corruption and potential privilege escalation within the host kernel; it does not cross a VM, container, or IOMMU security boundary.\nC:H - KASAN reports a slab use-after-free read through dangling chunk-\u003etransport in sctp_check_transmitted(); UAF on sctp_transport objects can be groomed for arbitrary kernel memory disclosure.\nI:H - The UAF dereference performs flight_size arithmetic on a freed sctp_transport slab object, enabling heap grooming and arbitrary kernel write or control-flow hijack primitives typical of SCTP transport UAFs.\nA:H - Accessing freed transport memory during SACK processing can cause kernel oops/panic and repeatable remote denial of service against any SCTP endpoint handling the malicious peer traffic."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-25T05:40:15.097Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/6575fb17230814b48b471727c8410c0aadff9274"
},
{
"url": "https://git.kernel.org/stable/c/6b9e2ea2057113f3393990ba646d2d97c719a80d"
},
{
"url": "https://git.kernel.org/stable/c/874a7c2b5e184f06134fdfde27e9ce9271bafe58"
},
{
"url": "https://git.kernel.org/stable/c/1adf929121e13e0b19200bb9fef715b918d483fe"
},
{
"url": "https://git.kernel.org/stable/c/e2e7c1de0e226ca1b7fea2de57a6c9bca408709b"
},
{
"url": "https://git.kernel.org/stable/c/2b3b5eec8b2c30ee237e3c31a6a38de9c39d804d"
},
{
"url": "https://git.kernel.org/stable/c/5ccf35ef0ed6059cdf8b1f4606a6584d5b67166b"
},
{
"url": "https://git.kernel.org/stable/c/9f2cf069a9a72a2d6b97ca8b4c70e714aac99749"
}
],
"title": "sctp: keep chunk-\u003etransport in step with the list it is queued on",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74588",
"datePublished": "2026-08-22T15:31:40.466Z",
"dateReserved": "2026-08-15T05:44:03.918Z",
"dateUpdated": "2026-08-25T05:40:15.097Z",
"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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