CVE intelligence

CVE-2026-72221

Vulnerability intelligence

Published Aug 15, 2026Sources checked Nov 10, 2026

9.8CRITICALCVSS out of 10

What this means

Review the available evidence

CVE-2026-72221 and is rated Critical severity with a CVSS score of 9.8. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Ubuntu Security Notices guidance

Vendor revision: Oct 2, 2026

Vendor remediation details

This update corrects flaws in the following subsystems: - ARM64 architecture; - S390 architecture; - x86 architecture; - DRBD Distributed Replicated Block Device drivers; - InfiniBand drivers; - IOMMU subsystem; - Multiple devices driver; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - NVME drivers; - TCM subsystem; - Virtio Host (VHOST) subsystem; - Xen hypervisor drivers; - AFS file system; - File systems infrastructure; - Network file systems library; - Network file system (NFS) client; - NTFS3 file system; - OCFS2 file system; - OrangeFS file system; - SMB network file system; - IPv4 networking; - Sun RPC protocol; - IPv6 networking; - IP tunnels definitions; - Netfilter; - TCP network protocol; - Locking primitives; - 9P file system network protocol; - B.A.T.M.A.

Ubuntu Security Notices guidance

Vendor revision: Sep 30, 2026

Vendor remediation details

Ubuntu Security Notices guidance

Vendor revision: Sep 29, 2026

Vendor remediation details

CISA KEVNot listedBased on the latest collected catalog

EPSS0.6%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-72221?

In the Linux kernel, the following vulnerability has been resolved:

sunrpc: wait for in-flight TLS handshake callback when cancel loses race

When wait_for_completion_interruptible_timeout() in svc_tcp_handshake() returns 0 (timeout) or -ERESTARTSYS (signal) and tls_handshake_cancel() then returns false, handshake_complete() has won the cancellation race: it has set HANDSHAKE_F_REQ_COMPLETED and is about to invoke svc_tcp_handshake_done(), but the callback's side effects on xpt_flags and on svsk->sk_handshake_done have not yet committed.

The current code reads xpt_flags immediately to decide whether the session succeeded. Two races result.

If the callback has executed set_bit(XPT_TLS_SESSION) but not yet clear_bit(XPT_HANDSHAKE), svc_tcp_handshake() sees a session, enqueues the transport, and returns. svc_xprt_received() then clears XPT_BUSY, a worker thread picks the transport up, the dispatcher in svc_handle_xprt() observes XPT_HANDSHAKE still set, and xpo_handshake is invoked a second time.

That svc_tcp_handshake() calls init_completion(&svsk->sk_handshake_done) while the original callback concurrently calls complete_all() on it, corrupting the embedded swait_queue.

If the callback has set HANDSHAKE_F_REQ_COMPLETED but not yet entered svc_tcp_handshake_done(), svc_tcp_handshake() reads XPT_TLS_SESSION as clear and tears the connection down even though the handshake is about to succeed.

Wait for the callback to commit before inspecting xpt_flags. The completion is guaranteed to fire because handshake_complete() invokes svc_tcp_handshake_done() unconditionally once it has set HANDSHAKE_F_REQ_COMPLETED.

Source: NVD