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CriticalFix available

sctp: purge outqueue on stale COOKIE-ECHO handling

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: sctp: purge outqueue on stale COOKIE-ECHO handling sctp_stream_update() is only invoked when the association is moved into COOKIE_WAIT during association setup/reconfiguration. In this path, the outbound stream scheduler state (stream->out_curr) is expected to be clean, since no user data should have been transmitted yet unless the state machine has already partially progressed. However, a corner case exists in sctp_sf_do_5_2_6_stale(): when a Stale Cookie ERROR is received, the association is rolled back from COOKIE_ECHOED to COOKIE_WAIT. In this scenario, user data may already have been queued and even bundled with the COOKIE-ECHO chunk. During the rollback, sctp_stream_update() frees the old stream table and installs a new one, but it does not invalidate stream->out_curr. As a result, out_curr may still point to a freed sctp_stream_out entry from the previous stream state. Later, SCTP scheduler dequeue paths (FCFS, RR, PRIO, etc.) rely on stream->out_curr->ext, which can lead to use-after-free once the old stream state has been released via sctp_stream_free(). This results in crashes such as (reported by Yuqi): BUG: KASAN: slab-use-after-free in sctp_sched_fcfs_dequeue+0x13a/0x140 Read of size 8 at addr ff1100004d4d3208 by task mini_poc/9312 CPU: 1 UID: 1001 PID: 9312 Comm: mini_poc Not tainted 7.1.0-rc1-00305-gbd3a4795d574 #5 PREEMPT(full) sctp_sched_fcfs_dequeue+0x13a/0x140 sctp_outq_flush+0x1603/0x33e0

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.259, 5.15.210, 6.1.176, 6.12.94, 6.18.36, 6.6.143, 7.0.13
CVEs
CVE-2026-52924
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 15:18 UTC · Revision 1

Source evidence

sctp: purge outqueue on stale COOKIE-ECHO handling

core-osv · Original source

Published 24 Jun 2026, 07:14 UTC

In the Linux kernel, the following vulnerability has been resolved: sctp: purge outqueue on stale COOKIE-ECHO handling sctp_stream_update() is only invoked when the association is moved into COOKIE_WAIT during association setup/reconfiguration. In this path, the outbound stream scheduler state (stream->out_curr) is expected to be clean, since no user data should have been transmitted yet unless the state machine has already partially progressed. However, a corner case exists in sctp_sf_do_5_2_6_stale(): when a Stale Cookie ERROR is received, the association is rolled back from COOKIE_ECHOED to COOKIE_WAIT. In this scenario, user data may already have been queued and even bundled with the COOKIE-ECHO chunk. During the rollback, sctp_stream_update() frees the old stream table and installs a new one, but it does not invalidate stream->out_curr. As a result, out_curr may still point to a freed sctp_stream_out entry from the previous stream state. Later, SCTP scheduler dequeue paths (FCFS, RR, PRIO, etc.) rely on stream->out_curr->ext, which can lead to use-after-free once the old stream state has been released via sctp_stream_free(). This results in crashes such as (reported by Yuqi): BUG: KASAN: slab-use-after-free in sctp_sched_fcfs_dequeue+0x13a/0x140 Read of size 8 at addr ff1100004d4d3208 by task mini_poc/9312 CPU: 1 UID: 1001 PID: 9312 Comm: mini_poc Not tainted 7.1.0-rc1-00305-gbd3a4795d574 #5 PREEMPT(full) sctp_sched_fcfs_dequeue+0x13a/0x140 sctp_outq_flush+0x1603/0x33e0

osv:CVE-2026-52924

Kernel

Fixed versions: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13

Complete source record
{
  "id": "296fd366c480deb21d534df667ad7055e18a69c4e5a931f3d7516899bcbbb933",
  "url": "https://osv.dev/vulnerability/CVE-2026-52924",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sctp: purge outqueue on stale COOKIE-ECHO handling",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: sctp: purge outqueue on stale COOKIE-ECHO handling sctp_stream_update() is only invoked when the association is moved into COOKIE_WAIT during association setup/reconfiguration. In this path, the outbound stream scheduler state (stream->out_curr) is expected to be clean, since no user data should have been transmitted yet unless the state machine has already partially progressed. However, a corner case exists in sctp_sf_do_5_2_6_stale(): when a Stale Cookie ERROR is received, the association is rolled back from COOKIE_ECHOED to COOKIE_WAIT. In this scenario, user data may already have been queued and even bundled with the COOKIE-ECHO chunk. During the rollback, sctp_stream_update() frees the old stream table and installs a new one, but it does not invalidate stream->out_curr. As a result, out_curr may still point to a freed sctp_stream_out entry from the previous stream state. Later, SCTP scheduler dequeue paths (FCFS, RR, PRIO, etc.) rely on stream->out_curr->ext, which can lead to use-after-free once the old stream state has been released via sctp_stream_free(). This results in crashes such as (reported by Yuqi): BUG: KASAN: slab-use-after-free in sctp_sched_fcfs_dequeue+0x13a/0x140 Read of size 8 at addr ff1100004d4d3208 by task mini_poc/9312 CPU: 1 UID: 1001 PID: 9312 Comm: mini_poc Not tainted 7.1.0-rc1-00305-gbd3a4795d574 #5 PREEMPT(full) sctp_sched_fcfs_dequeue+0x13a/0x140 sctp_outq_flush+0x1603/0x33e0 ",
    "evidence": "osv:CVE-2026-52924",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.259",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.210",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.176",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.143",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.94",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.36",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.13",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-52924",
      "aliases": [
        "CVE-2026-52924"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "f46e1d1a758878f0d22c4fbbd1bf42bb7165d1e8"
                },
                {
                  "fixed": "3c0741a441a7df7099d7ca6a64a6a0de09c677c8"
                },
                {
                  "fixed": "2afc9e684dc7fecf73db1edc937ebbc47b4b68dc"
                },
                {
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                {
                  "fixed": "a6207349e703cfc04756a4d16dec9176135813a5"
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                {
                  "fixed": "83ade59e5da365f4bf8bce72c5a38774202b442f"
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                {
                  "fixed": "e374b22e9b07b72a25909621464ff74096151bfb"
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              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52924.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.15.0"
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                {
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                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
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                {
                  "fixed": "5.15.210"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.176"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.94"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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              ]
            },
            {
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52924.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.700903911Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1d4652f677906a64487c13f9ace54b0eb263b5d0",
        "https://git.kernel.org/stable/c/2afc9e684dc7fecf73db1edc937ebbc47b4b68dc",
        "https://git.kernel.org/stable/c/3c0741a441a7df7099d7ca6a64a6a0de09c677c8",
        "https://git.kernel.org/stable/c/83ade59e5da365f4bf8bce72c5a38774202b442f",
        "https://git.kernel.org/stable/c/84b7a319105db2f917ccdcf502bdc866082b1285",
        "https://git.kernel.org/stable/c/a6207349e703cfc04756a4d16dec9176135813a5",
        "https://git.kernel.org/stable/c/e374b22e9b07b72a25909621464ff74096151bfb",
        "https://git.kernel.org/stable/c/f46e1d1a758878f0d22c4fbbd1bf42bb7165d1e8",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52924.json",
        "https://access.redhat.com/errata/RHSA-2026:59723",
        "https://access.redhat.com/errata/RHSA-2026:59737",
        "https://access.redhat.com/errata/RHSA-2026:59821",
        "https://access.redhat.com/errata/RHSA-2026:67471",
        "https://access.redhat.com/security/cve/CVE-2026-52924",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52924.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52924",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2492095",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52924.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52924",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496753,
  "published_at": "2026-06-24T07:14:18.646+00:00"
}