CVE-2024-39468

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

smb: client: fix deadlock in smb2_find_smb_tcon()

Unlock cifs_tcp_ses_lock before calling cifs_put_smb_ses() to avoid such deadlock.

A low impact deadlock flaw was found in the Linux kernel SMB client. The smb2_find_smb_tcon() function in fs/smb/client/smb2transport.c calls cifs_put_smb_ses() while still holding the cifs_tcp_ses_lock, which can result in a deadlock. A local user with low privileges able to trigger the affected CIFS/SMB client code path, for example through operations on mounted CIFS/SMB shares, could use this flaw to cause a kernel deadlock, resulting in a denial of service; confidentiality and integrity are not impacted. Red Hat Enterprise Linux 9 (kernel and kernel-rt) is affected by this flaw, while Red Hat Enterprise Linux 6, 7, and 8, Fedora, and Red Hat's hosted OpenShift cluster services are not affected. The fix for the affected Red Hat Enterprise Linux 9 streams is currently deferred: because this flaw is rated Low impact and only affects the availability of systems using the kernel CIFS/SMB client, it will be addressed in a future planned update rather than an immediate update. Until the fix is delivered, the residual risk is that a local user could hang an affected system that uses CIFS/SMB mounts. This differs from the CVE.org record, which scores the issue as 7.5 with a network attack vector; Red Hat and NIST both assess it as 5.5 with a local attack vector (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), consistent with the Low impact rating, because exploitation requires local access with privileges on a system using the kernel CIFS/SMB client.

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 for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.