CVE-2025-38440

A flaw was found in the Linux kernel's net/mlx5e driver. A race condition exists between disabling Dynamic Interrupt Moderation (DIM) and New API (NAPI) callbacks. This timing issue can lead to a NULL pointer dereference, which results in a kernel panic and a system crash, causing a Denial of Service (DoS). A local attacker with low privileges could potentially exploit this vulnerability.

A moderate-severity denial of service flaw was found in the Linux kernel's net/mlx5e driver. A race condition exists between disabling Dynamic Interrupt Moderation (DIM) and NAPI callback processing: if a NAPI callback observes the DIM state bit as set but DIM is disabled immediately afterwards, the dim pointer on the receive or send queue may already be NULL, causing a NULL pointer dereference in net_dim() that leads to a kernel panic and a system crash. A local attacker with low privileges could potentially exploit this timing window to cause a denial of service; there is no impact on confidentiality or integrity. The kernel and kernel-rt packages in Red Hat Enterprise Linux 9 and Red Hat Enterprise Linux 10 are affected, and the fix has been deferred to a future scheduled kernel update because of the moderate severity and the practical difficulty of exploiting the race: it requires local access and winning a narrow timing window. The residual risk of deferral is limited to local denial of service on systems using affected mlx5e network hardware. Red Hat Enterprise Linux 6, 7, and 8, and Red Hat In-Vehicle OS, are not affected because the vulnerable code is not present in those versions. Red Hat rates this flaw as Moderate severity (CVSS 3.1 score 4.7, AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H), reflecting that exploitation requires local access with high attack complexity and affects availability only. This differs from the upstream CVE record's rating of 7.8 (Important), which assumes low attack complexity and confidentiality and integrity impacts that the Red Hat analysis does not support.

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.