Vulnerability-Lookup

GHSA-3H9M-XFJQ-9F2F

Vulnerability from github – Published: 2025-12-09 03:31 – Updated: 2025-12-09 03:31

Details

In the Linux kernel, the following vulnerability has been resolved:

smc: Fix use-after-free in tcp_write_timer_handler().

With Eric's ref tracker, syzbot finally found a repro for use-after-free in tcp_write_timer_handler() by kernel TCP sockets. [0]

If SMC creates a kernel socket in __smc_create(), the kernel socket is supposed to be freed in smc_clcsock_release() by calling sock_release() when we close() the parent SMC socket.

However, at the end of smc_clcsock_release(), the kernel socket's sk_state might not be TCP_CLOSE. This means that we have not called inet_csk_destroy_sock() in __tcp_close() and have not stopped the TCP timers.

The kernel socket's TCP timers can be fired later, so we need to hold a refcnt for net as we do for MPTCP subflows in mptcp_subflow_create_socket().

[0]: leaked reference. sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108) inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244) __sock_create (net/socket.c:1546) smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284) __sock_create (net/socket.c:1546) __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661) __x64_sys_socket (net/socket.c:1672) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) ================================================================== BUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) Read of size 1 at addr ffff888052b65e0d by task syzrepro/18091

CPU: 0 PID: 18091 Comm: syzrepro Tainted: G W 6.3.0-rc4-01174-gb5d54eb5899a #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:107) print_report (mm/kasan/report.c:320 mm/kasan/report.c:430) kasan_report (mm/kasan/report.c:538) tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643) call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701) __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022) run_timer_softirq (kernel/time/timer.c:2037) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572) __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650) irq_exit_rcu (kernel/softirq.c:664) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))

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{
  "affected": [],
  "aliases": [
    "CVE-2023-53781"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-09T01:16:49Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmc: Fix use-after-free in tcp_write_timer_handler().\n\nWith Eric\u0027s ref tracker, syzbot finally found a repro for\nuse-after-free in tcp_write_timer_handler() by kernel TCP\nsockets. [0]\n\nIf SMC creates a kernel socket in __smc_create(), the kernel\nsocket is supposed to be freed in smc_clcsock_release() by\ncalling sock_release() when we close() the parent SMC socket.\n\nHowever, at the end of smc_clcsock_release(), the kernel\nsocket\u0027s sk_state might not be TCP_CLOSE.  This means that\nwe have not called inet_csk_destroy_sock() in __tcp_close()\nand have not stopped the TCP timers.\n\nThe kernel socket\u0027s TCP timers can be fired later, so we\nneed to hold a refcnt for net as we do for MPTCP subflows\nin mptcp_subflow_create_socket().\n\n[0]:\nleaked reference.\n sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108)\n inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244)\n __sock_create (net/socket.c:1546)\n smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284)\n __sock_create (net/socket.c:1546)\n __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661)\n __x64_sys_socket (net/socket.c:1672)\n do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)\n==================================================================\nBUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)\nRead of size 1 at addr ffff888052b65e0d by task syzrepro/18091\n\nCPU: 0 PID: 18091 Comm: syzrepro Tainted: G        W          6.3.0-rc4-01174-gb5d54eb5899a #7\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014\nCall Trace:\n \u003cIRQ\u003e\n dump_stack_lvl (lib/dump_stack.c:107)\n print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)\n kasan_report (mm/kasan/report.c:538)\n tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)\n tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643)\n call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701)\n __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022)\n run_timer_softirq (kernel/time/timer.c:2037)\n __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572)\n __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650)\n irq_exit_rcu (kernel/softirq.c:664)\n sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))\n \u003c/IRQ\u003e",
  "id": "GHSA-3h9m-xfjq-9f2f",
  "modified": "2025-12-09T03:31:10Z",
  "published": "2025-12-09T03:31:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53781"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1cc41c8acfc1ee30b4868559058db97fa44b0137"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9744d2bf19762703704ecba885b7ac282c02eacf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2023-53781 (GCVE-0-2023-53781)

Vulnerability from cvelistv5 – Published: 2025-12-09 00:00 – Updated: 2025-12-09 00:00

Title

smc: Fix use-after-free in tcp_write_timer_handler().

Summary

In the Linux kernel, the following vulnerability has been resolved: smc: Fix use-after-free in tcp_write_timer_handler(). With Eric's ref tracker, syzbot finally found a repro for use-after-free in tcp_write_timer_handler() by kernel TCP sockets. [0] If SMC creates a kernel socket in __smc_create(), the kernel socket is supposed to be freed in smc_clcsock_release() by calling sock_release() when we close() the parent SMC socket. However, at the end of smc_clcsock_release(), the kernel socket's sk_state might not be TCP_CLOSE. This means that we have not called inet_csk_destroy_sock() in __tcp_close() and have not stopped the TCP timers. The kernel socket's TCP timers can be fired later, so we need to hold a refcnt for net as we do for MPTCP subflows in mptcp_subflow_create_socket(). [0]: leaked reference. sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108) inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244) __sock_create (net/socket.c:1546) smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284) __sock_create (net/socket.c:1546) __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661) __x64_sys_socket (net/socket.c:1672) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) ================================================================== BUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) Read of size 1 at addr ffff888052b65e0d by task syzrepro/18091 CPU: 0 PID: 18091 Comm: syzrepro Tainted: G W 6.3.0-rc4-01174-gb5d54eb5899a #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014 Call Trace: <IRQ> dump_stack_lvl (lib/dump_stack.c:107) print_report (mm/kasan/report.c:320 mm/kasan/report.c:430) kasan_report (mm/kasan/report.c:538) tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594) tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643) call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701) __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022) run_timer_softirq (kernel/time/timer.c:2037) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572) __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650) irq_exit_rcu (kernel/softirq.c:664) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14)) </IRQ>

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/1cc41c8acfc1ee30b…
	https://git.kernel.org/stable/c/9744d2bf197627037…

Impacted products

Vendor

Product

Version

Linux

Affected: ac7138746e14137a451f8539614cdd349153e0c0 , < 1cc41c8acfc1ee30b4868559058db97fa44b0137 (git)
Affected: ac7138746e14137a451f8539614cdd349153e0c0 , < 9744d2bf19762703704ecba885b7ac282c02eacf (git)

Linux

Affected: 4.11
Unaffected: 0 , < 4.11 (semver)
Unaffected: 6.2.12 , ≤ 6.2.* (semver)
Unaffected: 6.3 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/smc/af_smc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1cc41c8acfc1ee30b4868559058db97fa44b0137",
              "status": "affected",
              "version": "ac7138746e14137a451f8539614cdd349153e0c0",
              "versionType": "git"
            },
            {
              "lessThan": "9744d2bf19762703704ecba885b7ac282c02eacf",
              "status": "affected",
              "version": "ac7138746e14137a451f8539614cdd349153e0c0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/smc/af_smc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.11"
            },
            {
              "lessThan": "4.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.2.*",
              "status": "unaffected",
              "version": "6.2.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.2.12",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmc: Fix use-after-free in tcp_write_timer_handler().\n\nWith Eric\u0027s ref tracker, syzbot finally found a repro for\nuse-after-free in tcp_write_timer_handler() by kernel TCP\nsockets. [0]\n\nIf SMC creates a kernel socket in __smc_create(), the kernel\nsocket is supposed to be freed in smc_clcsock_release() by\ncalling sock_release() when we close() the parent SMC socket.\n\nHowever, at the end of smc_clcsock_release(), the kernel\nsocket\u0027s sk_state might not be TCP_CLOSE.  This means that\nwe have not called inet_csk_destroy_sock() in __tcp_close()\nand have not stopped the TCP timers.\n\nThe kernel socket\u0027s TCP timers can be fired later, so we\nneed to hold a refcnt for net as we do for MPTCP subflows\nin mptcp_subflow_create_socket().\n\n[0]:\nleaked reference.\n sk_alloc (./include/net/net_namespace.h:335 net/core/sock.c:2108)\n inet_create (net/ipv4/af_inet.c:319 net/ipv4/af_inet.c:244)\n __sock_create (net/socket.c:1546)\n smc_create (net/smc/af_smc.c:3269 net/smc/af_smc.c:3284)\n __sock_create (net/socket.c:1546)\n __sys_socket (net/socket.c:1634 net/socket.c:1618 net/socket.c:1661)\n __x64_sys_socket (net/socket.c:1672)\n do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)\n==================================================================\nBUG: KASAN: slab-use-after-free in tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)\nRead of size 1 at addr ffff888052b65e0d by task syzrepro/18091\n\nCPU: 0 PID: 18091 Comm: syzrepro Tainted: G        W          6.3.0-rc4-01174-gb5d54eb5899a #7\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.amzn2022.0.1 04/01/2014\nCall Trace:\n \u003cIRQ\u003e\n dump_stack_lvl (lib/dump_stack.c:107)\n print_report (mm/kasan/report.c:320 mm/kasan/report.c:430)\n kasan_report (mm/kasan/report.c:538)\n tcp_write_timer_handler (net/ipv4/tcp_timer.c:378 net/ipv4/tcp_timer.c:624 net/ipv4/tcp_timer.c:594)\n tcp_write_timer (./include/linux/spinlock.h:390 net/ipv4/tcp_timer.c:643)\n call_timer_fn (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/timer.h:127 kernel/time/timer.c:1701)\n __run_timers.part.0 (kernel/time/timer.c:1752 kernel/time/timer.c:2022)\n run_timer_softirq (kernel/time/timer.c:2037)\n __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:572)\n __irq_exit_rcu (kernel/softirq.c:445 kernel/softirq.c:650)\n irq_exit_rcu (kernel/softirq.c:664)\n sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1107 (discriminator 14))\n \u003c/IRQ\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-09T00:00:36.831Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1cc41c8acfc1ee30b4868559058db97fa44b0137"
        },
        {
          "url": "https://git.kernel.org/stable/c/9744d2bf19762703704ecba885b7ac282c02eacf"
        }
      ],
      "title": "smc: Fix use-after-free in tcp_write_timer_handler().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53781",
    "datePublished": "2025-12-09T00:00:36.831Z",
    "dateReserved": "2025-12-08T23:58:35.272Z",
    "dateUpdated": "2025-12-09T00:00:36.831Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-3H9M-XFJQ-9F2F

CVE-2023-53781 (GCVE-0-2023-53781)

Tags

Sightings

Nomenclature