CVE-2026-64380
smb: client: harden POSIX SID length parsing
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.
INFO
Published Date :
July 25, 2026, 10:17 a.m.
Last Modified :
July 25, 2026, 10:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-64380
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.
No affected product recoded yet
Solution
- Apply the latest Linux kernel security patches.
- Ensure POSIX SID length parsing is robust.
- Validate input boundaries for security helpers.
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-2026-64380.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64380 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-2026-64380
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-2026-64380 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64380 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.
-
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': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '171605aed68380c2fa75dff9b3a1ed427c50065b', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '4213c1208978483021d7d125c131de3985d38f61', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '96e889bc1e759c83f25093e8c2f3da31b4973f30', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '0de5b8e76847f5de26f364a82c6602c4881c30da', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '427eb7eb46425fec845a43e861f3d6e2899cae59', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '86c5d470f5d42e61123b2f4b4f0b91f4eee5b980', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '46a84715a015cb48e1b9c219dc88c03d8a541ea4', 'versionType': 'git'}, {'status': 'affected', 'version': '349e13ad30b45998bb9937cfe0b32be6f951976d', 'lessThan': '7ad2bcf2441430bb2e918fb3ef9a90d775a6e422', 'versionType': 'git'}], 'programFiles': ['fs/smb/client/smb2pdu.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/smb/client/smb2pdu.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely. Added Reference https://git.kernel.org/stable/c/0de5b8e76847f5de26f364a82c6602c4881c30da Added Reference https://git.kernel.org/stable/c/171605aed68380c2fa75dff9b3a1ed427c50065b Added Reference https://git.kernel.org/stable/c/4213c1208978483021d7d125c131de3985d38f61 Added Reference https://git.kernel.org/stable/c/427eb7eb46425fec845a43e861f3d6e2899cae59 Added Reference https://git.kernel.org/stable/c/46a84715a015cb48e1b9c219dc88c03d8a541ea4 Added Reference https://git.kernel.org/stable/c/7ad2bcf2441430bb2e918fb3ef9a90d775a6e422 Added Reference https://git.kernel.org/stable/c/86c5d470f5d42e61123b2f4b4f0b91f4eee5b980 Added Reference https://git.kernel.org/stable/c/96e889bc1e759c83f25093e8c2f3da31b4973f30