CVE-2025-21731
kernel: nbd: don't allow reconnect after disconnect
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · February 27, 2025
Updated · October 29, 2026
Description
A vulnerability was found in the Linux kernel's Network Block Device (NBD) subsystem, specifically involving a use-after-free (UAF) condition in the nbd_config structure. The root cause is the improper handling of the NBD_RT_BOUND flag during the disconnect process. The fix involves clearing the NBD_RT_BOUND flag in nbd_genl_disconnect() to prevent reconfiguration after disconnection.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 6.7CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CWE-416 · Use After Free