Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4 ntfs3 fs/ntfs3/index.c indx_insert_into_buffer buffer overflow

CVSS Meta Temp Score
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4.2$0-$5k0.97

Summaryinfo

A vulnerability described as problematic has been identified in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4. Affected by this vulnerability is the function indx_insert_into_buffer of the file fs/ntfs3/index.c of the component ntfs3. The manipulation results in buffer overflow. This vulnerability is cataloged as CVE-2026-72191. The attack must be initiated from a local position. There is no exploit available.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4. Affected is the function indx_insert_into_buffer of the file fs/ntfs3/index.c of the component ntfs3. The manipulation with an unknown input leads to a buffer overflow vulnerability. CWE is classifying the issue as CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. This is going to have an impact on integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ntfs3: validate split-point offset in indx_insert_into_buffer indx_insert_into_buffer() computes used = used1 - to_copy - sp_size; memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off)); where sp and sp_size come from hdr_find_split(). hdr_find_split() walks entries by le16_to_cpu(e->size) without validating that each step stays within hdr->used or that the size field is at least sizeof(struct NTFS_DE). index_hdr_check(), the on-load gatekeeper, only validates header-level fields (used, total, de_off) and does not walk per-entry sizes. A crafted NTFS image whose leaf INDEX_HDR reports used == total but contains one interior NTFS_DE with size = 0xFFF0 therefore passes validation, descends to indx_insert_into_buffer() through the ntfs_create() -> indx_insert_entry() path, and makes hdr_find_split() return an sp whose sp_size (0xFFF0) greatly exceeds the remaining bytes in the buffer. The u32 subtraction underflows and the memmove count becomes a near-4-GiB value, producing an out-of-bounds kernel write that corrupts adjacent allocations and panics the kernel. Reproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a single 'touch' inside the mounted directory; crash site resolves to fs/ntfs3/index.c at the memmove. Trigger requires only local mount of an attacker-supplied filesystem image (USB, loopback, or removable media auto-mount). Reject the split whenever the chosen sp plus its declared size already extends past hdr1->used. This is the minimal fix; it preserves the existing hdr_find_split() contract and relies on the same out: cleanup path as the pre-existing error returns. A prior OOB read in the very same indx_insert_into_buffer() memmove was fixed in commit b8c44949044e ("fs/ntfs3: Fix OOB read in indx_insert_into_buffer") by tightening hdr_find_e(), but that fix does not cover the split-point size field path addressed here: sp is returned by hdr_find_split(), not hdr_find_e(), and the underflow is driven by sp->size rather than hdr->used exceeding hdr->total.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-72191 since 08/09/2026. The exploitability is told to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch b232eb5c9fe11ec2368e9b565db69c724c35fbd2/7bf74e6baf810fe325f111996496c678fc6e244f/f3624cc069195001c88df7a291af215f2133ff2c/1758a564b6ebe7f4a82f23c9851d1cae15549457/f1df9d771df47aa40de6d70949c28720ae1e430d is able to eliminate this problem.

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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: 4.4
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.4
VulDB Temp Score: 4.2
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: Buffer overflow
CWE: CWE-120 / 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 6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc1
Patch: b232eb5c9fe11ec2368e9b565db69c724c35fbd2/7bf74e6baf810fe325f111996496c678fc6e244f/f3624cc069195001c88df7a291af215f2133ff2c/1758a564b6ebe7f4a82f23c9851d1cae15549457/f1df9d771df47aa40de6d70949c28720ae1e430d

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72191 (🔒)
GCVE (CVE): GCVE-0-2026-72191
GCVE (VulDB): GCVE-100-390654

Entryinfo

Created: 08/15/2026 13:41
Changes: 08/15/2026 13:41 (60)
Complete: 🔍
Cache ID: 216::103

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