AUGUST 16, 2026
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Case File

CVE-2026-68299

HIGH · CVSS 7.5 EPSS 0.45%

Source: NVD + CISA KEV + EPSS · Published 2026-08-10 · Last synced 2026-08-16

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's vmxnet3 driver, specifically in the handling of Geneve-encapsulated packets, where the function vmxnet3_get_hdr_len() incorrectly assumes the outer header is always present. This can lead to critical errors, including system crashes, when the outer protocol differs from the expected TCP, or when there is a mismatch between outer and inner IP versions. Organizations using Linux systems with vmxnet3 for network virtualization should prioritize addressing this issue to prevent potential disruptions in network operations.

CVE
CVE-2026-68299
Severity
HIGH
CVSS
7.5
EPSS
0.45%
Linux

Original NVD Description

In the Linux kernel, the following vulnerability has been resolved: vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets vmxnet3_get_hdr_len() assumes gdesc->rcd.v4/v6/tcp always describe the outer header, but for a Geneve-encapsulated packet the device can set them based on the inner header instead, signalled by the VMXNET3_RCD_HDR_INNER_SHIFT bit in the completion descriptor. Since the function never skips the outer encapsulation, this mismatch triggers: - BUG_ON(hdr.ipv4->protocol != IPPROTO_TCP), because the outer protocol is UDP (Geneve), not TCP. - BUG_ON(hdr.eth->h_proto != ...), when the tunnel's outer and inner IP versions differ (e.g. outer IPv6/inner IPv4 or vice versa). Check VMXNET3_RCD_HDR_INNER_SHIFT up front and bail out, since the function cannot locate the inner header it would need to parse. Also convert the remaining BUG_ON()s in this function to return 0 defensively.