Vulnerability-Lookup

GHSA-3VFV-7X6V-8JG6

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

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.

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "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"
    }
  ]
}

CVE-2026-74688 (GCVE-0-2026-74688)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-25 05:41

Title

sctp: clear control chunk transport if it is being removed

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.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/dbb3f418a8665ffb0…
https://git.kernel.org/stable/c/fad4766a74220fe57…
https://git.kernel.org/stable/c/936658ec41c28c397…
https://git.kernel.org/stable/c/8de65194a04d2552c…
https://git.kernel.org/stable/c/6160e756db81d6cb6…
https://git.kernel.org/stable/c/18d704bdd809377df…
https://git.kernel.org/stable/c/4d6b9cac6df5e0cfe…
https://git.kernel.org/stable/c/c9158ceaf27780ef6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < dbb3f418a8665ffb0514e1a9520ab6a1c5d4d886 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < fad4766a74220fe579c6fcaa10ba01c23529814f (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < 936658ec41c28c397ef390140e02d4c91ade92f0 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < 8de65194a04d2552cd39b6c67d942d490f22d174 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < 6160e756db81d6cb63e3e2952efcf6c5134be385 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < 18d704bdd809377dfd81a3c2f42426763b5da227 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < 4d6b9cac6df5e0cfef1a66b3edd7aebdb9e4b7e7 (git) Affected: 8a07eb0a50aebc8c95478d49c28c7f8419a26cef , < c9158ceaf27780ef64534ad72f44ffde3f8ccc49 (git)
Linux	Linux	Affected: 3.1 Unaffected: 0 , < 3.1 (semver) Unaffected: 5.10.265 , ≤ 5.10.* (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sctp/associola.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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            {
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              "versionType": "git"
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            {
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              "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",
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              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
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              "status": "unaffected",
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      "cpeApplicability": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.1",
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                {
                  "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
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        {
          "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."
        }
      ],
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        {
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            "baseSeverity": "CRITICAL",
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            "version": "3.1"
          },
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            {
              "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",
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        },
        {
          "url": "https://git.kernel.org/stable/c/c9158ceaf27780ef64534ad72f44ffde3f8ccc49"
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      "title": "sctp: clear control chunk transport if it is being removed",
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  "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"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-3VFV-7X6V-8JG6

CVE-2026-74688 (GCVE-0-2026-74688)

Tags

Sightings

Nomenclature