CVE-2026-23282: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23282 is a Linux kernel vulnerability in the SMB2 client's smb2_unlink() function caused by uninitialized variables. When SMB2_open_init() or SMB2_close_init() fails — for example, during a reconnect — the I/O vectors (iovs) set in @rqst are left uninitialized, causing a kernel oops when SMB2_open_free(), SMB2_close_free(), or smb2_set_related() are subsequently called on them. Affected kernel versions include 6.17, 6.17.1 through 6.18.16, and 6.19 through 6.19.6, as well as pre-release 7.0-rc1 and 7.0-rc2. It was published on March 25, 2026, with a CVSS v3.1 base score of 5.5 (Medium) (Red Hat Advisory, Red Hat Bugzilla).

The root cause is classified under CWE-824 (Access of Uninitialized Pointer) and CWE-908 (Use of Uninitialized Resource). In the smb2_unlink() function of the Linux kernel's SMB client, if SMB2_open_init() or SMB2_close_init() returns an error (e.g., due to a network reconnection event), the @open_iov and @close_iov variables are never initialized before being referenced in @rqst. Subsequent calls to cleanup or related-request functions then dereference these uninitialized pointers, triggering a kernel oops. The fix initializes @close_iov and @open_iov before they are assigned to @rqst, ensuring safe cleanup even on early failure paths (Red Hat Bugzilla, Kernel Patch 1).

Successful exploitation causes a kernel oops (crash), resulting in a denial of service on systems using the Linux kernel SMB client. The vulnerability has no confidentiality or integrity impact — only availability is affected. Systems that rely on SMB client functionality for network file access are at risk, particularly in environments where SMB reconnection events can be triggered by network instability or adversarial conditions (Red Hat Advisory).

Apply the upstream kernel patches available in versions 6.18.17, 6.19.7, and 7.0-rc3, which initialize @close_iov and @open_iov before use in smb2_unlink(). Patches are available via the upstream kernel stable tree (Kernel Patch 1, Kernel Patch 2, Kernel Patch 3). Amazon Linux 2023 users should apply the update referenced in ALAS2023-2026-1596. As a temporary workaround where patching is not immediately possible, disabling SMB client functionality on non-essential systems can reduce exposure.