CVE-2025-21731— nbd: don't allow reconnect after disconnect
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I. Basic Information for CVE-2025-21731
Vulnerability Information
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Vulnerability Title
nbd: don't allow reconnect after disconnect
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: nbd: don't allow reconnect after disconnect Following process can cause nbd_config UAF: 1) grab nbd_config temporarily; 2) nbd_genl_disconnect() flush all recv_work() and release the initial reference: nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd->recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -> due to step 1), reference is still not zero 3) nbd_genl_reconfigure() queue recv_work() again; nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -> succeed if (!test_bit(NBD_RT_BOUND, ...)) -> succeed nbd_reconnect_socket queue_work(nbd->recv_workq, &args->work) 4) step 1) release the reference; 5) Finially, recv_work() will trigger UAF: recv_work nbd_config_put(nbd) -> nbd_config is freed atomic_dec(&config->recv_threads) -> UAF Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 资源管理错误漏洞
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存在资源管理错误漏洞，该漏洞源于nbd在断开连接后允许重新连接，可能导致释放后重用。
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
II. Public POCs for CVE-2025-21731
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Same Patch Batch · Linux · 2025-02-27 · 177 CVEs total
| CVE-2025-21756 | 7.8 HIGH | vsock: Keep the binding until socket destruction |
| CVE-2025-21773 | can: etas_es58x: fix potential NULL pointer dereference on udev->serial | |
| CVE-2025-21763 | neighbour: use RCU protection in __neigh_notify() | |
| CVE-2025-21762 | arp: use RCU protection in arp_xmit() | |
| CVE-2025-21764 | ndisc: use RCU protection in ndisc_alloc_skb() | |
| CVE-2025-21765 | ipv6: use RCU protection in ip6_default_advmss() | |
| CVE-2025-21766 | ipv4: use RCU protection in __ip_rt_update_pmtu() | |
| CVE-2025-21767 | clocksource: Use migrate_disable() to avoid calling get_random_u32() in atomic context | |
| CVE-2025-21769 | ptp: vmclock: Add .owner to vmclock_miscdev_fops | |
| CVE-2025-21768 | net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels | |
| CVE-2025-21771 | sched_ext: Fix incorrect autogroup migration detection | |
| CVE-2025-21770 | iommu: Fix potential memory leak in iopf_queue_remove_device() | |
| CVE-2025-21777 | ring-buffer: Validate the persistent meta data subbuf array | |
| CVE-2025-21783 | gpiolib: Fix crash on error in gpiochip_get_ngpios() | |
| CVE-2025-21781 | batman-adv: fix panic during interface removal | |
| CVE-2025-21780 | drm/amdgpu: avoid buffer overflow attach in smu_sys_set_pp_table() | |
| CVE-2025-21779 | KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel | |
| CVE-2025-21778 | tracing: Do not allow mmap() of persistent ring buffer | |
| CVE-2025-21774 | can: rockchip: rkcanfd_handle_rx_fifo_overflow_int(): bail out if skb cannot be allocated | |
| CVE-2025-21772 | partitions: mac: fix handling of bogus partition table |
Showing top 20 of 177 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
- CVE-2026-46333
ptrace: slightly saner 'get_dumpable()' logic - CVE-2026-43490
ksmbd: validate inherited ACE SID length - CVE-2026-43489
liveupdate: luo_file: remember retrieve() status - CVE-2026-43487
ata: libata-core: Disable LPM on ST1000DM010-2EP102 - CVE-2026-43488
usb: xhci: Prevent interrupt storm on host controller error
Same vendor: Linux
- CVE-2026-46333
ptrace: slightly saner 'get_dumpable()' logic - CVE-2026-43490
ksmbd: validate inherited ACE SID length - CVE-2026-43489
liveupdate: luo_file: remember retrieve() status - CVE-2026-43487
ata: libata-core: Disable LPM on ST1000DM010-2EP102 - CVE-2026-43488
usb: xhci: Prevent interrupt storm on host controller error
V. Comments for CVE-2025-21731
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