CVE-2026-64437
Linux ksmbd use-after-free via SMB2_CLOSE then SMB2_CANCEL (auth required).
Is CVE-2026-64437 being exploited?
Not confirmed. CVE-2026-64437 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 0.43% probability of exploitation in the next 30 days.
How severe is CVE-2026-64437?
CVE-2026-64437 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-2026-64437?
Yes. A fix has been recorded for CVE-2026-64437. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64437 affect?
CVE-2026-64437 affects Linux kernel (ksmbd module), SMB servers using ksmbd, Linux distributions shipping vulnerable kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64437?
Install kernel update with ksmbd fix, restrict SMB access, require strong auth and reboot hosts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated SMB client can trigger a kernel use-after-free, causing crash (DoS) and potentially privilege escalation or arbitrary code execution.
Immediate action required
- affected>= b7063c7426ea5a4d15e01b60538718765392f49d and < a796ba4e61d5e14e07b79a359faac69f8f9b22a3
- affected>= 0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd and < b8e274e69ab09222c7a552c7c0c1eef9ce627fc1
- affected>= 89ae9df09d2c1fb4a4eb495c113a7ce1dca34147 and < ddb9239828336b36d8a3ef5943fdffb2f55b6508
- affected>= 14d2eee0193ac3cd1bf3d014373449f0b8d35d6d and < 94083db751930b1540ddff2b54d4677549c57f81
- affected>= f580d27e8928828693df44ba2db0fffdbe11dfea and < 12c36c99655f325befe50c26842f7deca414c381
- affected>= f580d27e8928828693df44ba2db0fffdbe11dfea and < 10f293a07f9e10e988b0ae44e2e99c631f5a68e0
- affected2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694
- affected>= 6.1.176 and < 6.1.178
- affected>= 6.6.143 and < 6.6.145
- affected>= 6.12.94 and < 6.12.96
- affected>= 6.18.36 and < 6.18.39
- affected>= 7.0.13 and < 7.1
- affected7.1
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.