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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2025-21731 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/6bef6222a3f6c7adb6396f77f25a3579d821b09a kernel.org Patch 
https://git.kernel.org/stable/c/844b8cdc681612ff24df62cdefddeab5772fadf1 kernel.org Patch 
https://git.kernel.org/stable/c/9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302 kernel.org Patch 
https://git.kernel.org/stable/c/a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739 kernel.org Patch 
https://git.kernel.org/stable/c/d208d2c52b652913b5eefc8ca434b0d6b757f68f kernel.org Patch 
https://git.kernel.org/stable/c/e3be8862d73cac833e0fb7602636c19c6cb94b11 kernel.org Patch 
https://git.kernel.org/stable/c/e70a578487a47d7cf058904141e586684d1c3381 kernel.org Patch 
https://git.kernel.org/stable/c/e7343fa33751cb07c1c56b666bf37cfca357130e kernel.org Patch 
https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html CVE
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html CVE

Weakness Enumeration

CWE-ID CWE Name Source
CWE-416 Use After Free CISA-ADP  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

5 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-21731
NVD Published Date:
02/26/2025
NVD Last Modified:
11/03/2025
Source:
kernel.org