Linux kernel nfsd bug affects widely deployed NFS servers; kernel-level UAF can crash or enable RCE across enterprises.
CVE-2026-89688
Linux nfsd kernel use-after-free enabling remote DoS or potential RCE
Is CVE-2026-89688 being exploited?
Not confirmed. CVE-2026-89688 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 0.61% probability of exploitation in the next 30 days.
How severe is CVE-2026-89688?
CVE-2026-89688 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-2026-89688?
Yes. A fix has been recorded for CVE-2026-89688. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89688 affect?
CVE-2026-89688 affects Linux kernel (nfsd) - NFS servers, Enterprise Linux distributions with affected kernels, Systems exporting NFS shares. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89688?
Apply kernel update containing nfsd fix, restart NFS, and block untrusted NFS clients until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote NFS client can trigger a kernel use-after-free via seqid_op replay, causing crash (DoS) or possible root RCE.
Immediate action required
- affected>= eec7620800081e27dbf8019ac2e66259f0d5bf6f and < 69ed78b6b947c9257213164678b4edf17533093b
- affected>= eec7620800081e27dbf8019ac2e66259f0d5bf6f and < 00843074d9b84824552c9679d423d29500ca5de0
- affected>= eec7620800081e27dbf8019ac2e66259f0d5bf6f and < f7cb90ddc021747fc9abfd4cf5252d425fd34eec
- affected>= eec7620800081e27dbf8019ac2e66259f0d5bf6f and < 5e4627d3513e60accfce9d5f4c7fa95251ef93d6
- affected6.10
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.