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.
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.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 16 Sep 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | nvdimm/btt: reject an arena whose nfree is below the lane count | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-16T10:32:46.769Z
Reserved: 2026-09-11T19:38:34.778Z
Link: CVE-2026-89965
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-16T11:17:07.033
Modified: 2026-09-16T11:17:07.033
Link: CVE-2026-89965
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.