The Linux kernel contains a flaw in the vdpa_sim module where a valid ASID may be assigned to a group index that equals the number of groups, causing an out-of-bounds write. This memory corruption can overwrite kernel data structures. The underlying weakness is an out-of-bounds write (CWE‑787).

The vulnerability affects the Linux kernel for all released versions that have not incorporated the bound-check patch referenced in commit 406db68f9cb976a8ddfafd631197264f2307e9c9. Any system running such a kernel and using the vdpa_sim interface, particularly within virtualized environments, is susceptible.

The CVSS score is 7.0, indicating high severity. EPSS information is not available and the issue is not listed in the CISA KEV catalog, so the exact likelihood of exploitation is unknown. Nevertheless, an out-of-bounds write in kernel space is high-severity. Based on the description, it is inferred that an attacker with local or privileged access capable of assigning an ASID to a group index equal to ngroups could trigger the vulnerability.