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Critical

sctp: fix use-after-free of cached ASCONF chunk

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: sctp: fix use-after-free of cached ASCONF chunk addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal ASCONF-ACK completion path releases the chunk and clears the pointer. However, sctp_asconf_queue_teardown() releases the cached chunk without clearing addip_last_asconf. During peer restart handling, sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes sctp_asconf_queue_teardown() while the association remains alive and leaves the pointer dangling. A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(), which accesses the stale chunk and passes it to sctp_process_asconf_ack(), causing a use-after-free and a second release. Clearing the pointer exposes a race with T4 expiry. Peer restart handling queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses timer_delete(), which does not wait for a callback already running on another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after the purge and dereference NULL. Clear addip_last_asconf after releasing the cached chunk, and make sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding ASCONF remains.

Announced Source revision 1
Original source ↗

CVE-2026-74587

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-74587

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "10459b03e2d9ee12435e96f587de4d4cacdbf435",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "e1bb114e09372fd6e03387ced9ef566da336ed6c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "179676f0166230c80053a392303485b37c93dd33",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "618b5c6d049896fcfabb91afc072954c92cb2693",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "07daf4f9750104960a1d60831b2353c0d41f35fb",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "d949992bc3f00027a2c755e860a11950c75f6073",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a000c01e60e40e15304ffe48fff051d17a7bea91",
        "lessThan": "8c283e7b56adce00193837f3311b06662466fb21",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sctp/associola.c",
      "net/sctp/sm_statefuns.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "3.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "3.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.265",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.152",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.104",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.45",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sctp/associola.c",
      "net/sctp/sm_statefuns.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74587

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33223 · Revision 1
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Publisher date
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