ksmbd: require source read access for duplicate extents (CVE-2026-64395) | HOL Guard CVE

High · CVSS 7.5CVE-2026-64395

ksmbd: require source read access for duplicate extents

Answer in brief

CVE-2026-64395 records a High severity (CVSS 7.5) vulnerability in ksmbd: require source read access for duplicate extents. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 25, 2026Updated Sep 4, 2026Source checked Sep 20, 2026First seen by HOL Aug 5, 2026Material review Sep 4, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:o:linux:linux_kernel::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=eb817368f50c1cbe1bd07044124aad7db6330e3a <2d2ab6983620c2d60ce7db72133984ca3873b929 \|\| >=eb817368f50c1cbe1bd07044124aad7db6330e3a <67bdad9cf01b25030e3bf00bbce6c309319d6663 \|\| >=eb817368f50c1cbe1bd07044124aad7db6330e3a <b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f \|\| >=eb817368f50c1cbe1bd07044124aad7db6330e3a <db231af842868268839f9f9619c68cb27830d8be \|\| >=eb817368f50c1cbe1bd07044124aad7db6330e3a <a10942af27832c2761d020863a46e79bebe0567d \|\| >=eb817368f50c1cbe1bd07044124aad7db6330e3a <cedff600f1642aa982178503552f0d007bc829c8	2d2ab6983620c2d60ce7db72133984ca3873b929, 67bdad9cf01b25030e3bf00bbce6c309319d6663, b0d4d5cb846a1ddb7aaab9adfb5986e4540e6e5f, db231af842868268839f9f9619c68cb27830d8be, a10942af27832c2761d020863a46e79bebe0567d, cedff600f1642aa982178503552f0d007bc829c8
Linux/Linuxgeneric	5.15	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 2d2ab6983620c2d60ce7db72133984ca3873b929 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 4, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: require source read access for duplicate extents FSCTL_DUPLICATE_EXTENTS_TO_FILE passes the source file directly to vfs_clone_file_range() or vfs_copy_file_range() without checking the SMB access mask granted to the source handle. A handle opened with attribute access can consequently be used to copy file contents into an attacker-readable destination. Require FILE_READ_DATA on the source handle before either VFS operation, matching other ksmbd data-copy paths.

Quoted source text, attributed separately from HOL analysis.