CVE-2026-99122

High

Description

In the Linux kernel, the following vulnerability has been resolved: vsock/vmci: validate packet source for connected sockets vmci_transport_recv_stream_cb() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback can select a non-listening socket without checking whether the packet came from its stored peer. This was reproduced with two VMCI contexts. A RST from the context not stored in a TCP_SYN_SENT socket reset that socket after it was selected by the destination-only lookup. VMCI can process notification packets in bottom-half context when the socket is not owned by user context, or defer packets to a workqueue. Use vsock_check_source() after taking the socket lock in the bottom-half path, and recheck after lock_sock() in the workqueue path. Listening sockets continue to accept packets from any source. Reply with a RST addressed from the received packet before dropping a source that fails validation. This preserves the existing reset behavior for bound non-listening and concurrently closed sockets without directing the reset to a connected socket's stored peer.

SeverityHigh
CVSS7.3
Exploit probability—
ProductMicrosoft Azl3 Kernel
PublishedOct 28, 2026
First seenNov 4, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
microsoft azl3_kernel_6.6.157.1-1No range specified—
microsoft azl3_kernel_6.6.159.1-1No range specified—

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