Affects the Linux kernel NFS server (widely deployed); kernel memory corruption can disrupt infrastructure and enables escalation or RCE.
CVE-2026-89703
Use-after-free in Linux nfsd (NFSv4) causing kernel memory corruption.
Is CVE-2026-89703 being exploited?
Not confirmed. CVE-2026-89703 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-2026-89703?
CVE-2026-89703 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-2026-89703?
Yes. A fix has been recorded for CVE-2026-89703. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89703 affect?
CVE-2026-89703 affects Linux kernel (nfsd NFSv4 server). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89703?
Install vendor/kernel updates that include the nfsd fix and reboot NFS servers.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Use-after-free in nfsd can cause kernel memory corruption leading to crashes, privilege escalation, or potential remote code execution.
Immediate action required
- affected>= 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a and < d832a0587528853d45481d1faf75d4b5d062adaf
- affected>= 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a and < 1e4795766719ffd74b8cf0f2fde4a1350f8326bf
- affected>= 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a and < a6d89032e5c6620d5bb44582a72555ce07bf1c2e
- affected>= 8dd91e8d31febf4d9cca3ae1bb4771d33ae7ee5a and < 650d370cfbc66a96dd14d517bd704689b5bda4e5
- affected967faa26f313a62e7bebc55d5b8122eaee43b929
- affected>= 6.11.6 and < 6.12
- 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.