Affects the Linux kernel's NFSv4.1 implementation used widely on servers and storage; can cause kernel memory corruption/DoS or RCE, risking broad infrastructure impact.
CVE-2026-90104
Linux NFSv4.1 kernel bug causing memory corruption via uninitialized callback lists.
Is CVE-2026-90104 being exploited?
Not confirmed. CVE-2026-90104 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.
How severe is CVE-2026-90104?
CVE-2026-90104 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-2026-90104?
Yes. A fix has been recorded for CVE-2026-90104. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-90104 affect?
CVE-2026-90104 affects Linux kernel with NFSv4.1 enabled, NFS clients and servers using callback sequences, Enterprise 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-2026-90104?
Install vendor kernel update or apply the kernel patch; disable NFSv4.1 callbacks if unpatchable.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote kernel memory corruption via NFSv4.1 callback handling; can cause DoS (kernel panic) and potentially privilege escalation or RCE.
Immediate action required
- affected>= 4aece6a19cf7f474f15eb861ba74db4479884ce3 and < f31f3c042e024aef437cda42f0424ae8d4594b6c
- affected>= 4aece6a19cf7f474f15eb861ba74db4479884ce3 and < 8fa4804fe62ca4155a2d8fc2789d630376cbf2fc
- affected2.6.31
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.