In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.

A flaw was found in the Linux kernel's Common Internet File System (CIFS) implementation. Incorrect locking mechanisms were used for `tcon` fields, where the `cifs_tcp_ses_lock` was applied too broadly instead of more granular locks. This improper locking could lead to concurrency issues within the kernel, potentially resulting in system instability or a denial of service (DoS).

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-43215 https://nvd.nist.gov/vuln/detail/CVE-2026-43215 https://lore.kernel.org/linux-cve-announce/2026050650-CVE-2026-43215-7e04@gregkh/T