Affects widely-used Linux kernel ksmbd; could disrupt many deployments.
CVE-2026-31706
Linux ksmbd SMB DACL handling allows oversized allocation via tampered NTACL.
Is CVE-2026-31706 being exploited?
Not confirmed. CVE-2026-31706 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.37% probability of exploitation in the next 30 days.
How severe is CVE-2026-31706?
CVE-2026-31706 is rated High. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-31706?
Yes. A fix has been recorded for CVE-2026-31706. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-31706 affect?
CVE-2026-31706 affects Linux kernel ksmbd (SMB server). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-31706?
Patch kernel promptly
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated SMB client can trigger an 8 MB uninitialized allocation during DACL inheritance, causing DoS/kernel crash; potential overflow on 32-bit.
Patch when possible
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 063a7409b0de46d7c770b65bb0338e6fdb3b1f0a
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 3e5360b422dd741cb315654a191fa73869a37414
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 59c32abaaec9cdd6164811c7e864e72f7554b82d
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 3e4e2ea2a781018ed5d75f969e3e5606beb66e48
- affected5.15
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.