CVE-2026-23102: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23102 is an out-of-bounds read vulnerability in the Linux kernel's arm64/fpsimd signal handling subsystem, specifically in the restoration of SVE (Scalable Vector Extension) context when SME (Scalable Matrix Extension) is supported. The flaw can place a task into an invalid state where SVCR.SM is set and sve_state is non-NULL but TIF_SME is clear, leading to out-of-bounds memory reads and potential task termination via SIGKILL. It affects Linux kernel versions from 5.19 up to (but not including) 6.1.162, 6.2 up to 6.6.123, 6.7 up to 6.18.8, and pre-release 6.19-rc1 through rc6. The vulnerability was published on February 4, 2026, with patches added on March 19, 2026. It carries a CVSS v3.1 base score of 7.1 (High) (Feedly).

The root cause is an out-of-bounds read (CWE-125 / CAPEC-540: Overread Buffers) in the kernel's SVE signal context restoration path on arm64 systems with SME support. When a signal context with SVE_SIG_FLAG_SM set is restored — either because userspace modified the context or it was saved from another task (e.g., via CRIU) — the kernel may set SVCR.SM without also setting TIF_SME. In this invalid state, task_fpsimd_load() skips configuring SMCR_ELx, leaving an arbitrary hardware value in place; if SMCR_ELx.LEN exceeds the task's allocated streaming SVE vector length, sve_load_state() reads memory outside the task's sve_state allocation. A second issue involves incorrect handling of the SVE_SIG_FLAG_SM flag when the task does not have an allocated sve_state, potentially causing a fatal kernel fault. Exploitation requires local access with low privileges and no user interaction (Feedly, Kernel Patch 1).

Successful exploitation can result in out-of-bounds kernel memory reads (confidentiality impact) and task termination via SIGKILL or a fatal kernel fault (availability impact). An attacker with local access on an arm64 system supporting SME could read unintended kernel memory contents, potentially exposing sensitive data from adjacent memory regions. Integrity is not directly impacted, but the ability to trigger kernel faults could be leveraged for denial-of-service conditions on affected systems (Feedly).

The Linux kernel maintainers have released patches addressing this vulnerability across multiple stable branches. Fixed versions include kernel 6.1.162, 6.6.123, and 6.18.8, with patches committed to the stable tree on March 19, 2026. Downstream distributions including SUSE, Ubuntu, and Amazon Linux 2023 have issued updated kernel packages incorporating these fixes. Administrators should update to a patched kernel version as soon as possible; no configuration-based workaround is known. Detection plugins are available via Nessus (IDs: 297969, 303406, 304219, 312152, 318847) and Qualys for identifying vulnerable systems (Feedly, SUSE Advisory, Ubuntu Advisory, Amazon Linux).

Vendor advisories have been issued by SUSE, Ubuntu, and Amazon Linux 2023 addressing this vulnerability as part of broader kernel update packages. No notable independent researcher commentary or significant social media discussion has been identified for this CVE. Coverage has been limited to standard vulnerability tracking and advisory channels (SUSE Advisory, Ubuntu Advisory).