Linux kernel vulnerability impacting SMB client in widely deployed kernels; can crash or enable kernel RCE on many systems — merits org-wide attention.
CVE-2026-64386
Linux SMB client double-free allows remote kernel memory corruption or crash
Is CVE-2026-64386 being exploited?
Not confirmed. CVE-2026-64386 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-2026-64386?
CVE-2026-64386 is rated Critical with a CVSS score of 9.8. 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-2026-64386?
Yes. A fix has been recorded for CVE-2026-64386. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64386 affect?
CVE-2026-64386 affects Linux kernel (SMB client/CIFS/SMB2/SMB3), Linux distributions using affected kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64386?
Apply vendor kernel updates/backports immediately and block untrusted SMB servers
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attacker controlling an SMB server can trigger a double-free in the kernel, causing crashes or potential remote code execution on clients.
Immediate action required
- affected>= 433042a91f9373241307725b52de573933ffedbf and < 100fb7c455fa86d248b8bd7bb9de757c192870b4
- affected>= 4f1fffa2376922f3d1d506e49c0fd445b023a28e and < 3c81dda84799f76b42aec598564316e2964440db
- affected>= 4f1fffa2376922f3d1d506e49c0fd445b023a28e and < f1add4acb656f5a82806a1ab0e63fed3d8b1bfca
- affected>= 4f1fffa2376922f3d1d506e49c0fd445b023a28e and < 89234773e8348918111aa15f6922b58cf3843364
- affected>= 4f1fffa2376922f3d1d506e49c0fd445b023a28e and < 2a88561d66eb855813cf004a0abe648bbb17de5e
- affected>= 6.6.32 and < 6.6.145
- affected6.8
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.