CVE-2025-38102: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38102 is a race condition vulnerability in the Linux kernel's VMCI (Virtual Machine Communication Interface) subsystem, specifically between the vmci_host_setup_notify and vmci_ctx_unset_notify functions. The flaw was disclosed on July 3, 2025, and affects Linux kernel versions from 4.0 through multiple stable branches, with fixed versions including 5.4.296, 5.10.240, 5.15.186, 6.1.142, 6.6.94, 6.12.34, and 6.15.3. It carries a CVSS v3.1 base score of 7.0 (High) (Red Hat Advisory, Red Hat Bugzilla).

The vulnerability is classified as CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization). The root cause is that context->notify_page can be partially initialized by get_user_pages_fast in vmci_host_setup_notify on one CPU, while concurrently vmci_ctx_unset_notify on another CPU reads the partially-written pointer and calls put_page(), freeing the page before get_user_pages_fast completes. This triggers a kernel warning in try_grab_folio (mm/gup.c:147) via the call chain vmci_host_unlocked_ioctl → get_user_pages_fast → __gup_longterm_locked → __get_user_pages → follow_trans_huge_pmd → try_grab_folio. The fix uses a local variable to ensure notify_page is only made visible after get_user_pages_fast fully completes (Red Hat Bugzilla, Kernel Patches).

A local attacker with low privileges could exploit this race condition to cause kernel warnings, memory corruption, or potentially trigger unauthorized memory operations through the VMCI subsystem. The vulnerability has high confidentiality, integrity, and availability impact ratings, meaning successful exploitation could lead to system instability, kernel crashes, or potentially unauthorized access to kernel memory. The attack complexity is rated High, as it requires precise timing to win the race condition between two concurrent VMCI operations (Red Hat Advisory).

There is no public proof-of-concept exploit code and no evidence of in-the-wild exploitation as of the disclosure date. The vulnerability has an EPSS score of approximately 0.024% (0.000240), 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 with low privileges and high attack complexity due to the timing-dependent nature of the race condition (Red Hat Advisory).

The primary remediation is to update to a patched Linux kernel version. Fixed versions include: 5.4.296, 5.10.240, 5.15.186, 6.1.142, 6.6.94, 6.12.34, and 6.15.3. Patches are available from the upstream kernel stable tree and have been incorporated into vendor-specific updates from Red Hat, Debian (DSA-5973-1, DLA-4327-1), Ubuntu (USN-7769-1, USN-7770-1, USN-7771-1, USN-7774-2, USN-7775-1, USN-7789-1), SUSE, Amazon Linux 2, and Oracle Linux. As a workaround, restricting local user access to VMCI devices can reduce exposure until patching is feasible (Red Hat Bugzilla, Kernel Patches).