CVE-2026-90176
ksmbd: Do not skip lock checks for single-byte ranges
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: Do not skip lock checks for single-byte ranges check_lock_range() uses inclusive ranges. Its callers pass the end offset as start + length - 1, so start == end represents a valid single-byte range rather than an empty range. The start == end shortcut therefore skips mandatory byte-range lock checks for one-byte reads, writes, copychunk operations and one-byte truncate ranges. A conflicting lock covering that byte is not checked and the operation is allowed to proceed. Remove the shortcut. The truncate size == inode->i_size case is already handled by only calling check_lock_range() when the new size differs from the current file size.
INFO
Published Date :
Sept. 17, 2026, 5:17 p.m.
Last Modified :
Sept. 18, 2026, 6:17 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Remove the start == end shortcut in check_lock_range().
- Ensure lock checks are performed for all byte ranges.
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-2026-90176.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-90176 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-2026-90176
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).
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The following list is the news that have been mention
CVE-2026-90176 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-90176 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.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 17, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: ksmbd: Do not skip lock checks for single-byte ranges check_lock_range() uses inclusive ranges. Its callers pass the end offset as start + length - 1, so start == end represents a valid single-byte range rather than an empty range. The start == end shortcut therefore skips mandatory byte-range lock checks for one-byte reads, writes, copychunk operations and one-byte truncate ranges. A conflicting lock covering that byte is not checked and the operation is allowed to proceed. Remove the shortcut. The truncate size == inode->i_size case is already handled by only calling check_lock_range() when the new size differs from the current file size. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/90xxx/CVE-2026-90176.json">CVE-2026-90176</a> Added Reference https://git.kernel.org/stable/c/07a9e289ff7edcc004f58952405f8a65c4e37512 Added Reference https://git.kernel.org/stable/c/84c2d8e807ac489f5c91769293fb15dfdae8bae8 Added Reference https://git.kernel.org/stable/c/993e0158331d37c04da18efe551b5e1e35fb3078 Added Reference https://git.kernel.org/stable/c/a89cc145832e81c32199d4ca2e1ea8bd51ed601d Added Reference https://git.kernel.org/stable/c/d40c24634fe077a0dc91fd11fccf44ce12b454d5 Added Reference https://git.kernel.org/stable/c/f751d6e39d4c937c45f8fedc66699aa7d2d52288