Linux kernel vulnerability in NFS/SUNRPC impacts many servers and storage setups; kernel-level corruption can disrupt enterprise infrastructure.
CVE-2026-89546
Linux kernel NFS backchannel race causing use-after-free and memory corruption
Is CVE-2026-89546 being exploited?
Not confirmed. CVE-2026-89546 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 0.52% probability of exploitation in the next 30 days.
How severe is CVE-2026-89546?
CVE-2026-89546 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-2026-89546?
Yes. A fix has been recorded for CVE-2026-89546. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89546 affect?
CVE-2026-89546 affects Linux kernel (SUNRPC/NFS callback), NFS servers and clients using callback/backchannel, Major Linux distributions (Ubuntu, RHEL, SUSE, Debian). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89546?
Apply vendor kernel updates immediately; reboot and restart NFS services; isolate NFS hosts until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
NFS backchannel race can cause use-after-free/memory corruption, allowing kernel crashes, privilege escalation, or possible remote code execution via NFS traffic.
Immediate action required
- affected>= 441244d4273a8037b265fd254dfdaca5fa736ee2 and < 6debde9e3e6ae21dcca75837b4247b13ca4ea2b8
- affected>= 441244d4273a8037b265fd254dfdaca5fa736ee2 and < 3674f780f47d2906b5a0f7199b66973067bdfeca
- affected6.19
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.