CVE-2026-64394
Linux ksmbd allows unauthorized ACL/owner changes via SMB2 SET_INFO SECURITY.
Is CVE-2026-64394 being exploited?
Not confirmed. CVE-2026-64394 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 0.47% probability of exploitation in the next 30 days.
How severe is CVE-2026-64394?
CVE-2026-64394 is rated High with a CVSS score of 8.8. 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-2026-64394?
Yes. A fix has been recorded for CVE-2026-64394. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64394 affect?
CVE-2026-64394 affects Linux kernel (ksmbd SMB server), Linux servers with in-kernel SMB enabled. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64394?
Apply vendor kernel update or backport ksmbd fix immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attacker with a handle can rewrite file DACL/owner, enabling privilege escalation and unauthorized file access.
Patch when possible
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 0848b1d8b403f530878195dcbe241a2fddb9d0e1
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < e6aa731f1b4b3e08caebf66a99f04b22bdab2e99
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 9ab2ffd3ed3d4ca1667c52de27026ddabc11e537
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < f56535db508ead8dec1c481ad93d7d8acd8f8f1e
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < aae600cdaffc6d9ce97645f129799a103a97d06d
- affected>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 and < 44df157a1183a7f746caa970c169255da5ac61f8
- 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.