CVE-2026-31432: Linux kernel · Out-of-bounds Write
Source GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in fda9522ed6afaec45cabc198d8492270c394c7bc : patch Linux kernel soon.
Data as of 30 Oct 2026, 16:33 UTC
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 8.8 |
|---|
- Patch
- Available – fixed in fda9522ed6afaec45cabc198d8492270c394c7bc, d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09, 850452af77f55d185f9445e1f7a1db53c5e4aad4 +5
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-31432 (opens in a new tab)
- git.kernel.org/stable/c/075ea208c648cc2bcd616295b711d3637c61de45 (opens in a new tab)
- git.kernel.org/stable/c/515c2daab46021221bdf406bef19bc90a44ec617 (opens in a new tab)
- git.kernel.org/stable/c/533f84264e28c54a79257ea87d2f94a0fcc9a611 (opens in a new tab)
- git.kernel.org/stable/c/850452af77f55d185f9445e1f7a1db53c5e4aad4 (opens in a new tab)
- git.kernel.org/stable/c/d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09 (opens in a new tab)
- git.kernel.org/stable/c/fda9522ed6afaec45cabc198d8492270c394c7bc (opens in a new tab)