CVE-2026-102761

NetX Duo's WebSocket client resets the unmasking cursor to the first `NX_PACKET` each time it advances through a chained packet, while the loop's upper bound belongs to the current packet. With the standard contiguous packet-pool layout, a masked server frame split across two packets therefore drives the XOR loop through the first packet's unused payload area and on through the second packet's `NX_PACKET` control block. The four-byte WebSocket masking key controls the bytes written, so the corruption is attacker-chosen rather than incidental.

  • Published Sep 29, 2026
  • CVSS 9.3 critical
  • 0.3% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-102761 at the National Vulnerability Database