CVE-2026-64448
Linux SMB client bug can leak kernel memory or crash via a malicious SMB server
Is CVE-2026-64448 being exploited?
Not confirmed. CVE-2026-64448 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 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-64448?
CVE-2026-64448 is rated High with a CVSS score of 8.2. 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-2026-64448?
Yes. A fix has been recorded for CVE-2026-64448. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64448 affect?
CVE-2026-64448 affects Linux kernel smb/cifs client, SMB3 client (mount.cifs), cifs-utils, Linux distributions with affected kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64448?
Apply vendor kernel and cifs-utils updates; avoid mounting untrusted SMB servers.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Out-of-bounds reads in smb2_check_message allow kernel memory disclosure or crash (DoS) during NEGOTIATE/SESSION_SETUP from a malicious SMB server.
Patch when possible
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 8d0bbc78046d264bbf6a574ea6f9072258a43e35
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < b6a381c01e2ac98a48e32ac0f2a45bbadd9e26b0
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 31c6312608c60b72a1feb99a5afb680645a3e8a3
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 573e502d14714d2947e22e7eff40ec20a6a44a42
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 419ec1b604d7fb60c10aec2dc062371f9fcd4940
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < ceb875a375dedbf51c9425c1d13a2d7a8435c08c
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 6e9d10f62773b99bd927940fd9cbdfe7207e23ff
- affected>= 093b2bdad3221e3fae3c26d89387e7297a157664 and < 53b7c271f06be4dd5cfc8c6ef552a8355c891a7f
- affected3.6
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.