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CVE-2023-53781— smc: Fix use-after-free in tcp_write_timer_handler().

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于释放后重用问题。

CVSS 7.8 · High EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux ac7138746e14137a451f8539614cdd349153e0c0< 1cc41c8acfc1ee30b4868559058db97fa44b0137 affected
ac7138746e14137a451f8539614cdd349153e0c0< 9744d2bf19762703704ecba885b7ac282c02eacf affected
4.11 affected
< 4.11 unaffected
6.2.12≤ 6.2.* unaffected
6.3≤ * unaffected
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I. Basic Information for CVE-2023-53781

Vulnerability Information
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Vulnerability Title
smc: Fix use-after-free in tcp_write_timer_handler().
Source: CVE Program / CVE List V5
Vulnerability Description
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>
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于释放后重用问题。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux ac7138746e14137a451f8539614cdd349153e0c0 ~ 1cc41c8acfc1ee30b4868559058db97fa44b0137 -
Linux Linux 4.11 -

II. Public POCs for CVE-2023-53781

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III. Intelligence Information for CVE-2023-53781

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Same Patch Batch · Linux · 2025-12-09 · 152 CVEs total

CVE-2025-40343 9.8 CRITICAL nvmet-fc: avoid scheduling association deletion twice
CVE-2022-50666 9.8 CRITICAL RDMA/siw: Fix QP destroy to wait for all references dropped.
CVE-2023-53794 9.8 CRITICAL cifs: fix session state check in reconnect to avoid use-after-free issue
CVE-2025-40342 8.8 HIGH nvme-fc: use lock accessing port_state and rport state
CVE-2023-53785 8.8 HIGH mt76: mt7921: don't assume adequate headroom for SDIO headers
CVE-2023-53822 8.8 HIGH wifi: ath11k: Ignore frags from uninitialized peer in dp.
CVE-2025-40336 8.8 HIGH drm/gpusvm: fix hmm_pfn_to_map_order() usage
CVE-2023-53827 8.8 HIGH Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}
CVE-2025-40328 8.8 HIGH smb: client: fix potential UAF in smb2_close_cached_fid()
CVE-2023-53851 8.4 HIGH drm/msm/dp: Drop aux devices together with DP controller
CVE-2025-40337 8.2 HIGH net: stmmac: Correctly handle Rx checksum offload errors
CVE-2022-50656 8.1 HIGH nfc: pn533: Clear nfc_target before being used
CVE-2023-53803 8.1 HIGH scsi: ses: Fix slab-out-of-bounds in ses_enclosure_data_process()
CVE-2023-53800 7.8 HIGH ubi: Fix use-after-free when volume resizing failed
CVE-2023-53828 7.8 HIGH Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_add_adv_monitor()
CVE-2023-53829 7.8 HIGH f2fs: flush inode if atomic file is aborted
CVE-2023-53790 7.8 HIGH bpf: Zeroing allocated object from slab in bpf memory allocator
CVE-2023-53836 7.8 HIGH bpf, sockmap: Fix skb refcnt race after locking changes
CVE-2023-53844 7.8 HIGH drm/ttm: Don't leak a resource on swapout move error
CVE-2023-53846 7.8 HIGH f2fs: fix to do sanity check on direct node in truncate_dnode()

Showing top 20 of 152 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2023-53781

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