CVE-2026-53022: Linux Dell WMI Buffer Overflow – Kernel Denial of Service

Technical summary

The populate_enum_data() function in the dell-wmi-sysman driver concatenates firmware-supplied enumeration strings (value modifiers and possible values) into fixed-size 512-byte struct members. While individual source strings are bounded, the aggregation loop uses unbounded strcat() operations without tracking remaining buffer space. This allows a carefully constructed enumeration package with combined string lengths exceeding 512 bytes to overflow the destination buffer. The fix replaces raw string concatenation with a bounded append helper and adds validation to reject enumeration packages whose aggregated content exceeds buffer capacity.

Business impact

Systems relying on Dell WMI system management features are vulnerable to denial-of-service attacks via kernel crash. In multi-tenant or shared environments where local users have limited privileges, this could be weaponized for availability disruption. The vulnerability does not directly enable data theft or integrity compromise, but the kernel crash could interrupt critical services or trigger unexpected system restarts affecting operational continuity.

Affected systems

The Linux kernel is affected, specifically systems running kernel versions prior to the patch that include the dell-wmi-sysman driver. This affects Dell-branded systems or third-party hardware using Dell WMI system management interfaces. Users should verify their kernel version and Dell BIOS/system management feature usage against the kernel community's patch timeline.

Exploitability

Exploitation requires local system access and user-level (unprivileged) credentials. An attacker must supply crafted firmware data or manipulate system management parameters to trigger the overflow during driver initialization or reconfiguration. The vulnerability is not remotely exploitable and does not require elevated privileges, though the attacker must have system login access. No public exploit code or in-the-wild exploitation is currently documented.

Remediation

Apply the Linux kernel security patch that adds bounded string aggregation and validation checks to populate_enum_data(). This patch ensures that enumeration packages are rejected if their combined string content exceeds the 512-byte buffer limit. Systems should update to the patched kernel version and verify dell-wmi-sysman driver functionality after applying the update.

Patch guidance

Users should consult the Linux kernel security advisories and their distribution's kernel update channels for the patched version. Typically, major distributions (Red Hat, Ubuntu, Debian, SUSE) backport critical kernel fixes to supported releases. Verify the specific kernel version and release date against the advisory published 2026-06-24 and modified 2026-07-15. Test patches in non-production environments before broad rollout to ensure dell-wmi-sysman driver compatibility with your hardware configuration.

Detection guidance

Monitor system logs for kernel warnings or panics originating from the dell-wmi-sysman driver, particularly during system startup or when Dell system management utilities probe firmware settings. Use kernel debugging tools (dmesg, journalctl) to capture buffer overflow warnings or segmentation faults in the driver. On vulnerable systems, observe memory access violations or unexpected kernel crashes correlating with system management configuration changes. Intrusion detection systems may flag unusual firmware queries or repeated failed initialization attempts.

Why prioritize this

While the CVSS score of 5.5 (Medium) reflects local-only access requirements, the vulnerability should be prioritized in environments where local user access is common or where denial-of-service attacks impact critical infrastructure. Dell-branded enterprise systems and shared Linux servers warrant faster patching. However, internet-facing systems without local user accounts face minimal risk and may be deferred in favor of higher-severity remote vulnerabilities.

Risk score, explained

The CVSS 3.1 score of 5.5 (Medium, vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) reflects that the vulnerability requires local access (AV:L) with low attack complexity (AC:L) and low privileges (PR:L), but delivers high availability impact (A:H) through kernel crash. Confidentiality and integrity are not affected, limiting the score. The score appropriately reflects the narrow attack surface but significant availability risk for vulnerable systems.

Frequently asked questions