CVE-2026-31432 Details
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix OOB write in QUERY_INFO for compound requests When a compound request such as READ + QUERY_INFO(Security) is received, and the first command (READ) consumes most of the response buffer, ksmbd could write beyond the allocated buffer while building a security descriptor. The root cause was that smb2_get_info_sec() checked buffer space using ppntsd_size from xattr, while build_sec_desc() often synthesized a significantly larger descriptor from POSIX ACLs. This patch introduces smb_acl_sec_desc_scratch_len() to accurately compute the final descriptor size beforehand, performs proper buffer checking with smb2_calc_max_out_buf_len(), and uses exact-sized allocation + iov pinning.
A vulnerability allowing an out-of-bounds write has been identified in the Linux kernel's ksmbd component. This issue arises when a compound request, such as READ combined with QUERY_INFO(Security), is processed. If the READ command uses up most of the available response buffer, ksmbd may overwrite memory beyond the allocated buffer while creating a security descriptor. The problem occurs because the smb2_get_info_sec() function assesses buffer space using the ppntsd_size from extended attributes, while the build_sec_desc() function frequently generates a much larger descriptor based on POSIX ACLs. As a result, this vulnerability could potentially be exploited to corrupt memory or cause other unintended behaviors.
Users can upgrade to the latest version of the Linux kernel where this vulnerability has been patched. Instructions for upgrading the kernel can be found in the official Linux kernel documentation.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/075ea208c648cc2bcd616295b711d3637c61de45 | kernel.org | Patch |
| https://git.kernel.org/stable/c/515c2daab46021221bdf406bef19bc90a44ec617 | kernel.org | Patch |
| https://git.kernel.org/stable/c/850452af77f55d185f9445e1f7a1db53c5e4aad4 | kernel.org | |
| https://git.kernel.org/stable/c/d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09 | kernel.org | Patch |
| https://git.kernel.org/stable/c/fda9522ed6afaec45cabc198d8492270c394c7bc | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-787 | Out-of-bounds Write | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 5.15.145, < 5.16 >= 6.1.71, < 6.2 >= 6.6, < 6.12.81 >= 6.13, < 6.18.22 >= 6.19, < 6.19.12 7.0 rc1 7.0 rc2 7.0 rc3 7.0 rc4 7.0 rc5 7.0 rc6 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 19, 2026 | CVE Modified | kernel.org |
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 21, 2026 | Initial Analysis | [email protected] |
| Apr 27, 2026 | CVE Modified | kernel.org |
| Apr 22, 2026 | New CVE Received | kernel.org |