Kernel-level race in Linux sunrpc (NFS/RPC TLS) can corrupt kernel state or crash servers; affects widespread Linux infrastructure and requires org-wide action.
CVE-2026-72221
Linux sunrpc TLS handshake race can corrupt kernel state, causing crash or code execution.
Is CVE-2026-72221 being exploited?
Not confirmed. CVE-2026-72221 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 0.63% probability of exploitation in the next 30 days.
How severe is CVE-2026-72221?
CVE-2026-72221 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-2026-72221?
Yes. A fix has been recorded for CVE-2026-72221. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-72221 affect?
CVE-2026-72221 affects Linux kernel (sunrpc / svc_tcp_handshake), NFS servers using RPC over TLS, 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-2026-72221?
Apply vendor kernel security updates and reboot affected hosts immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote RPC clients can trigger a TLS handshake race to corrupt kernel wait-queues, causing kernel panic (DoS) or possible privilege escalation/remote code execution.
Immediate action required
- affected>= b3cbf98e2fdf3cb147a95161560cd25987284330 and < 0d8ceb39884148dc7a2fdf71e1cac5961ed1d2b9
- affected>= b3cbf98e2fdf3cb147a95161560cd25987284330 and < e0f4691d42a54d359d8b64509fd9ab938d4f2a33
- affected>= b3cbf98e2fdf3cb147a95161560cd25987284330 and < 65b23bec1fca6e9ebdc3e6041ebf8c6ab074141b
- affected>= b3cbf98e2fdf3cb147a95161560cd25987284330 and < a4f878e8ecd729ccf2e50993444e217583adeace
- affected>= b3cbf98e2fdf3cb147a95161560cd25987284330 and < d00e32f84ca1a77cb67a3fbf59f58dada95f5a21
- affected6.4
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.