GHSA-3VFV-7X6V-8JG6
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-74688"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:43Z",
"severity": "CRITICAL"
},
"details": "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.",
"id": "GHSA-3vfv-7x6v-8jg6",
"modified": "2026-08-25T06:31:27Z",
"published": "2026-08-22T18:30:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74688"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/18d704bdd809377dfd81a3c2f42426763b5da227"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4d6b9cac6df5e0cfef1a66b3edd7aebdb9e4b7e7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6160e756db81d6cb63e3e2952efcf6c5134be385"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8de65194a04d2552cd39b6c67d942d490f22d174"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/936658ec41c28c397ef390140e02d4c91ade92f0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c9158ceaf27780ef64534ad72f44ffde3f8ccc49"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dbb3f418a8665ffb0514e1a9520ab6a1c5d4d886"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fad4766a74220fe579c6fcaa10ba01c23529814f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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