Linux kernel bug affects many distributions and can compromise client kernels, causing widespread impact across enterprises.
CVE-2026-64066
Linux kernel netfs bug can allow kernel crash or compromise via network filesystem responses.
Is CVE-2026-64066 being exploited?
Not confirmed. CVE-2026-64066 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 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-64066?
CVE-2026-64066 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-2026-64066?
Yes. A fix has been recorded for CVE-2026-64066. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64066 affect?
CVE-2026-64066 affects Linux kernel (netfs), Network filesystem clients (NFS/CIFS/SMB), Vendor Linux kernels/distributions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64066?
Install vendor kernel patches and reboot; restrict or unmount untrusted network filesystems.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Failing/malformed netfs subrequests can trigger kernel crash, memory corruption, or local/remote privilege escalation on clients.
Immediate action required
- affected>= ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and < 884c4c4f35e577aba6a0593c80cbea9ca5e6e2b8
- affected>= ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and < 0256e79ce42101ad036edd4205bccca621ea0927
- affected>= ee4cdf7ba857a894ad1650d6ab77669cbbfa329e and < 8a8c0cfdf4658fc5b295b7fc87be56e0d76741f4
- affected6.12
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.