Linux Kernel up to 7.2.4 nvdimm/btt btt_freelist_init nfree out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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7.8$0-$5k0.00

Summaryinfo

A vulnerability described as very critical has been identified in Linux Kernel up to 7.2.4. This impacts the function btt_freelist_init of the component nvdimm/btt. Such manipulation of the argument nfree leads to out-of-bounds write. This vulnerability is listed as CVE-2026-89965. The attack must be carried out locally. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.4 and classified as very critical. Affected by this issue is the function btt_freelist_init of the component nvdimm/btt. The manipulation of the argument nfree with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-89965 since 09/11/2026. The exploitation is known to be easy. The attack needs to be approached locally. Additional levels of successful authentication are necessary for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/16/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch eb491343d2d1784121ad9af91c25b338c28913c3/59d5cd1f42b4bab3609512c3cb3d3540d3d21da7/f6c5313aae794ecca8f762c1a3493de5c266f120/f9bf05c63b77d000e9c01f3e47af36973887d350/6f79d1a5f2611a3d36e9312be5425cd9cb397c51/6b1faf1f099f7060b5f1f2f0d024132581f1726e/9dfa11cef4750b67591307f2c62e47a23d60e4b7/6a1f2e5ed9267ca19187038ac635393c165213ac is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 7.8

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.51/7.2.5/7.3-rc1
Patch: eb491343d2d1784121ad9af91c25b338c28913c3/59d5cd1f42b4bab3609512c3cb3d3540d3d21da7/f6c5313aae794ecca8f762c1a3493de5c266f120/f9bf05c63b77d000e9c01f3e47af36973887d350/6f79d1a5f2611a3d36e9312be5425cd9cb397c51/6b1faf1f099f7060b5f1f2f0d024132581f1726e/9dfa11cef4750b67591307f2c62e47a23d60e4b7/6a1f2e5ed9267ca19187038ac635393c165213ac

Timelineinfo

09/11/2026 CVE reserved
09/16/2026 +5 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-89965 (🔒)
GCVE (CVE): GCVE-0-2026-89965
GCVE (VulDB): GCVE-100-405788

Entryinfo

Created: 09/16/2026 14:57
Changes: 09/16/2026 14:57 (60)
Complete: 🔍
Cache ID: 216::103

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