CVE-2026-89965

7.8 HIGH

Published 2026-09-16 · Updated 2026-09-16

AI risk analysis

Summary: This vulnerability allows an attacker to perform an out-of-bounds write by providing a crafted arena with nfree below the lane count, potentially leading to kernel memory corruption.
Exploitability: Exploitation requires crafting a specific arena and injecting it into the system, which is moderately difficult and requires kernel-level access.
Blast radius: If exploited, the vulnerability could lead to arbitrary code execution with kernel privileges, impacting the entire system.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to the fixed version 5.19.1 or later.

kernelmemory-corruptionprivilege-escalation

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: nvdimm/btt: reject an arena whose nfree is below the lane count The BTT info block's nfree field, the number of reserve free blocks, is read from the medium without validation. btt_freelist_init() and btt_rtt_init() size the per-lane freelist[] and rtt[] arrays by nfree, but the I/O path indexes them by the lane from nd_region_acquire_lane(), which is bounded by nd_region->num_lanes (ND_MAX_LANES), not by nfree. A crafted or foreign arena whose nfree is below the lane count makes freelist[lane]/rtt[lane] run past the allocation: an out-of-bounds write. btt.rst documents the nlanes = min(nfree, num_cpus) invariant, which the code does not currently honor: num_lanes is ND_MAX_LANES regardless of nfree. Reject an arena whose nfree is below num_lanes at discovery, before the per-lane arrays are allocated, enforcing that invariant.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Data: NVD (public domain). Analysis: local $0 model. Defensive use only.