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CVE-2026-72383 (GCVE-0-2026-72383)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43
VLAI
Title
sctp: fix addr_wq_timer race in sctp_free_addr_wq()
Summary
In the Linux kernel, the following vulnerability has been resolved: sctp: fix addr_wq_timer race in sctp_free_addr_wq() sctp_free_addr_wq() previously removed addr_wq_timer using timer_delete() while holding addr_wq_lock. However, timer_delete() does not guarantee that a currently running timer handler has completed. This allows a race with sctp_addr_wq_timeout_handler(), where the handler may still run after addr_waitq has been freed, acquire addr_wq_lock, and access freed memory, leading to a use-after-free. Fix this by calling timer_shutdown_sync() before taking addr_wq_lock. This guarantees that any in-flight timer handler has finished and prevents the timer from being re-armed during teardown, making subsequent cleanup safe.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4db67e808640e3934d82ce61ee8e2e89fd877ba8 , < a8323fb2ab6cd6978f359daeed6688e0cadf32ba (git)
Affected: 4db67e808640e3934d82ce61ee8e2e89fd877ba8 , < c3e5cac47519d77ad36b9c03a1df1536aaa0c4a1 (git)
Affected: 4db67e808640e3934d82ce61ee8e2e89fd877ba8 , < 976c19de0f22a857ba0112f39635f8fd7a257568 (git)
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Linux Linux Affected: 3.7
Unaffected: 0 , < 3.7 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix addr_wq_timer race in sctp_free_addr_wq()\n\nsctp_free_addr_wq() previously removed addr_wq_timer using timer_delete()\nwhile holding addr_wq_lock. However, timer_delete() does not guarantee that\na currently running timer handler has completed.\n\nThis allows a race with sctp_addr_wq_timeout_handler(), where the handler\nmay still run after addr_waitq has been freed, acquire addr_wq_lock, and\naccess freed memory, leading to a use-after-free.\n\nFix this by calling timer_shutdown_sync() before taking addr_wq_lock.  This\nguarantees that any in-flight timer handler has finished and prevents the\ntimer from being re-armed during teardown, making subsequent cleanup safe."
        }
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "lang": "en",
              "value": "AV:L - The UAF is in sctp_free_addr_wq() during per-network-namespace SCTP teardown when a net namespace is destroyed; reaching it requires local syscalls (unshare/exit, SCTP socket/bind/setsockopt, rtnetlink address changes), not remote SCTP packet receive paths.\nAC:L - The attacker controls both sides of the race by creating a netns with SCTP AUTO_ASCONF sockets, queueing address events that arm addr_wq_timer (~500ms), and concurrently destroying that namespace; timer_delete() does not wait for sctp_addr_wq_timeout_handler(), so the UAF is reliably winnable.\nPR:L - An unprivileged local user can obtain CAP_NET_ADMIN in a new user+network namespace via unshare, bind an SCTP socket to INADDR_ANY, enable SCTP_AUTO_ASCONF, churn interface addresses to populate addr_waitq, and destroy the namespace; container tenants can trigger the same netns teardown without init-namespace root.\nUI:N - Exploitation is fully attacker-driven through scripted namespace create/configure/destroy and concurrent threads; no victim must mount filesystems, open files, or take any discretionary action beyond the attacker\u0027s own setup.\nS:U - The bug is kernel heap use-after-free of sctp_sockaddr_entry during netns teardown; impact is host kernel memory corruption and privilege escalation within the same kernel security authority, not a VM/hypervisor or IOMMU boundary crossing.\nC:H - sctp_addr_wq_timeout_handler() may walk addr_waitq and dereference sctp_sockaddr_entry fields after sctp_free_addr_wq() kfree()\u0027s those entries; UAF on freed heap objects enables kernel memory disclosure and supports further exploitation primitives.\nI:H - The timer handler calls sctp_asconf_mgmt() on corrupted addrw pointers (address family, sockaddr, state), driving ASCONF add/delete processing on freed memory; UAF heap corruption is exploitable for arbitrary kernel write and potential code execution.\nA:H - Use-after-free in sctp_addr_wq_timeout_handler() during list iteration, socket locking, and sctp_asconf_mgmt() can cause kernel oops or panic from accesses to freed sctp_sockaddr_entry memory, even when full exploitation is not attempted."
            }
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        "dateUpdated": "2026-08-17T05:43:34.215Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    "cveId": "CVE-2026-72383",
    "datePublished": "2026-08-15T05:56:14.755Z",
    "dateReserved": "2026-08-09T03:40:39.923Z",
    "dateUpdated": "2026-08-17T05:43:34.215Z",
    "state": "PUBLISHED"
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      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "sctp: fix addr_wq_timer race in sctp_free_addr_wq()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-72383.json",
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T17:43:25+00:00",
      "cve": "CVE-2026-72383",
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      "source": "Red Hat CSAF VEX",
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      "title": "kernel: sctp: fix addr_wq_timer race in sctp_free_addr_wq()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72383.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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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.


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