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9.1
CRITICAL CVSS 3.1
CVE-2026-64257
smb: client: reject overlapping data areas in SMB2 responses
Overview
Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions.

Details
INFO

Published Date :

July 25, 2026, 10:17 a.m.

Last Modified :

Aug. 17, 2026, 5:17 a.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-64257 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Address overlapping data areas in SMB2 responses to prevent improper length exceptions.
  • Track data area overlap separately.
  • Reject responses with overlapping data areas.
  • Apply length compatibility exceptions correctly.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-64257.

URL Resource
https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775 Patch
https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7 Patch
https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f Patch
https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460 Patch
https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe Patch
https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83 Patch
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64257 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-64257 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-64257 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-64257 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '31c6312608c60b72a1feb99a5afb680645a3e8a3', 'lessThan': '445ece263131780dee273d727a4d6f11934feec7', 'versionType': 'git'}, {'status': 'affected', 'version': '573e502d14714d2947e22e7eff40ec20a6a44a42', 'lessThan': '36bfa52459e45c0d5b668de2f1c91f6dc5c67775', 'versionType': 'git'}, {'status': 'affected', 'version': '419ec1b604d7fb60c10aec2dc062371f9fcd4940', 'lessThan': '4a9d2657d3e05f6ed09c148cb127b4e58702275f', 'versionType': 'git'}, {'status': 'affected', 'version': 'ceb875a375dedbf51c9425c1d13a2d7a8435c08c', 'lessThan': 'fdafa1e68dc75045b7b617e6e7d2854950804d83', 'versionType': 'git'}, {'status': 'affected', 'version': '6e9d10f62773b99bd927940fd9cbdfe7207e23ff', 'lessThan': '57cba95f0e97c6f6e45e6731da30aff091bd7460', 'versionType': 'git'}, {'status': 'affected', 'version': '53b7c271f06be4dd5cfc8c6ef552a8355c891a7f', 'lessThan': '8986c932905ea508d66da421eb2eb6e676ace1fe', 'versionType': 'git'}, {'status': 'affected', 'version': '8d0bbc78046d264bbf6a574ea6f9072258a43e35', 'versionType': 'git'}, {'status': 'affected', 'version': 'b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}], 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.2-rc3'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.2-rc3', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '31c6312608c60b72a1feb99a5afb680645a3e8a3', 'lessThan': '445ece263131780dee273d727a4d6f11934feec7', 'versionType': 'git'}, {'status': 'affected', 'version': '573e502d14714d2947e22e7eff40ec20a6a44a42', 'lessThan': '36bfa52459e45c0d5b668de2f1c91f6dc5c67775', 'versionType': 'git'}, {'status': 'affected', 'version': '419ec1b604d7fb60c10aec2dc062371f9fcd4940', 'lessThan': '4a9d2657d3e05f6ed09c148cb127b4e58702275f', 'versionType': 'git'}, {'status': 'affected', 'version': 'ceb875a375dedbf51c9425c1d13a2d7a8435c08c', 'lessThan': 'fdafa1e68dc75045b7b617e6e7d2854950804d83', 'versionType': 'git'}, {'status': 'affected', 'version': '6e9d10f62773b99bd927940fd9cbdfe7207e23ff', 'lessThan': '57cba95f0e97c6f6e45e6731da30aff091bd7460', 'versionType': 'git'}, {'status': 'affected', 'version': '53b7c271f06be4dd5cfc8c6ef552a8355c891a7f', 'lessThan': '8986c932905ea508d66da421eb2eb6e676ace1fe', 'versionType': 'git'}, {'status': 'affected', 'version': '8d0bbc78046d264bbf6a574ea6f9072258a43e35', 'versionType': 'git'}, {'status': 'affected', 'version': 'b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}], 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'unaffected'}]
  • Initial Analysis by [email protected]

    Aug. 12, 2026

    Action Type Old Value New Value
    Added CWE NVD-CWE-noinfo
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.2:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.10.261 up to (excluding) 5.11 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.15.212 up to (excluding) 5.16
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460 Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe Types: Patch
    Added Reference Type kernel.org: https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83 Types: Patch
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 27, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 25, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '31c6312608c60b72a1feb99a5afb680645a3e8a3', 'lessThan': '445ece263131780dee273d727a4d6f11934feec7', 'versionType': 'git'}, {'status': 'affected', 'version': '573e502d14714d2947e22e7eff40ec20a6a44a42', 'lessThan': '36bfa52459e45c0d5b668de2f1c91f6dc5c67775', 'versionType': 'git'}, {'status': 'affected', 'version': '419ec1b604d7fb60c10aec2dc062371f9fcd4940', 'lessThan': '4a9d2657d3e05f6ed09c148cb127b4e58702275f', 'versionType': 'git'}, {'status': 'affected', 'version': 'ceb875a375dedbf51c9425c1d13a2d7a8435c08c', 'lessThan': 'fdafa1e68dc75045b7b617e6e7d2854950804d83', 'versionType': 'git'}, {'status': 'affected', 'version': '6e9d10f62773b99bd927940fd9cbdfe7207e23ff', 'lessThan': '57cba95f0e97c6f6e45e6731da30aff091bd7460', 'versionType': 'git'}, {'status': 'affected', 'version': '53b7c271f06be4dd5cfc8c6ef552a8355c891a7f', 'lessThan': '8986c932905ea508d66da421eb2eb6e676ace1fe', 'versionType': 'git'}, {'status': 'affected', 'version': '8d0bbc78046d264bbf6a574ea6f9072258a43e35', 'versionType': 'git'}, {'status': 'affected', 'version': 'b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0', 'versionType': 'git'}, {'status': 'affected', 'version': '5.10.261', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.212', 'lessThan': '5.16', 'versionType': 'semver'}], 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '7.2-rc3'}, {'status': 'unaffected', 'version': '0', 'lessThan': '7.2-rc3', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/smb/client/smb2misc.c'], 'defaultStatus': 'affected'}]
    Added Description In the Linux kernel, the following vulnerability has been resolved: smb: client: reject overlapping data areas in SMB2 responses Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions.
    Added Reference https://git.kernel.org/stable/c/36bfa52459e45c0d5b668de2f1c91f6dc5c67775
    Added Reference https://git.kernel.org/stable/c/445ece263131780dee273d727a4d6f11934feec7
    Added Reference https://git.kernel.org/stable/c/4a9d2657d3e05f6ed09c148cb127b4e58702275f
    Added Reference https://git.kernel.org/stable/c/57cba95f0e97c6f6e45e6731da30aff091bd7460
    Added Reference https://git.kernel.org/stable/c/8986c932905ea508d66da421eb2eb6e676ace1fe
    Added Reference https://git.kernel.org/stable/c/fdafa1e68dc75045b7b617e6e7d2854950804d83
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.1
Attack Vector
Attack Complexity
Privileges Required
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Scope
Confidentiality Impact
Integrity Impact
Availability Impact