CVE-2025-38271: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38271 is a NULL pointer dereference vulnerability in the Linux kernel's network link creation path (rtnl_create_link()). The flaw occurs when dev->netdev_ops is NULL during link creation and CONFIG_NET_SHAPER is enabled, causing netdev_lock_ops() to dereference a NULL pointer. It affects Linux kernel versions 6.15 through 6.15.2 (fixed in 6.15.3). The vulnerability was published on July 10, 2025, and carries a CVSS v3.1 base score of 5.5 (Medium) (Feedly).

The root cause is a NULL pointer dereference (CWE-476) in net/core/rtnetlink.c. During rtnl_create_link(), the network device's netdev_ops pointer is not yet initialized, but the code calls dev_set_group(), which internally invokes netdev_lock_ops() — a function that dereferences dev->netdev_ops to determine locking requirements. When CONFIG_NET_SHAPER is defined, this code path is active and triggers the NULL dereference. The fix replaces the call to dev_set_group() with netif_set_group(), which does not require netdev_ops to be initialized (Feedly, Kernel Patch 1, Kernel Patch 2). The attack vector is local, requiring low privileges and no user interaction.

Successful exploitation causes a kernel NULL pointer dereference, resulting in a kernel panic or system crash — a complete denial of service of the affected host. There is no confidentiality or integrity impact; the vulnerability is limited to availability. A local user with sufficient privileges to create network links (e.g., via rtnetlink) on a kernel built with CONFIG_NET_SHAPER can trigger this crash (Feedly).

There is no known public exploit code or evidence of in-the-wild exploitation for CVE-2025-38271. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires local access and a kernel compiled with CONFIG_NET_SHAPER, limiting the practical attack surface (Feedly).

The vulnerability is patched in Linux kernel version 6.15.3. Two upstream commits address the issue: 8a29ae8428a5c26f0b4471c2057d9e9415c53109 and feafc73f3e6ae73371777a037d41d2e31c929636. Users running kernel 6.15.x should upgrade to 6.15.3 or later. As a temporary workaround, disabling CONFIG_NET_SHAPER at kernel build time prevents the vulnerable code path from being compiled in, though recompiling the kernel is required (Kernel Patch 1, Kernel Patch 2).