CVE-2026-68299

vmxnet3: fix BUG_ON in vmxnet3_get_hdr_len() for Geneve packets

State: Published
Severity: 7.5 High
Published: Aug 10, 2026
Updated: Oct 19, 2026
Reserved: Jul 30, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	Linux

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
LinuxLinux	45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before fbab6b73cc086e32698c86e43d1b16bf17d24c36Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 28e382646417c7e2be9c9a7079eddf627ff52b90Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 667b6e52048eaf4dbcf1707ed87ffd44abb9cb38Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 4fdb0f162ccdbe9626863b10003855703253fa29Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before b28596baf87e25a078789f1c05817c8a3bf71257Affected 45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 34a71f5361fc3adb5b7138da78750b0d535a8252Affected
LinuxLinux	4.2Affected before 4.2Not affected 5.10.265 through 5.10.Not affected 5.15.216 through 5.15.Not affected 6.1.183 through 6.1.Not affected 6.6.148 through 6.6.Not affected 6.12.101 through 6.12.Not affected 6.18.42 through 6.18.Not affected 7.1.6 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 2ddf51fcb6dd7d55ceef38e2e1a5ab2ab7fd47b0Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before fbab6b73cc086e32698c86e43d1b16bf17d24c36Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 28e382646417c7e2be9c9a7079eddf627ff52b90Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 667b6e52048eaf4dbcf1707ed87ffd44abb9cb38Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 28cb5d8d13b4c1faf3f688f62e5df82fe7b438d8Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 4fdb0f162ccdbe9626863b10003855703253fa29Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before b28596baf87e25a078789f1c05817c8a3bf71257Affected
45dac1d6ea045ae56e4df8d9c70c92c7412bd4fc to before 34a71f5361fc3adb5b7138da78750b0d535a8252Affected

LinuxLinux

4.2Affected
before 4.2Not affected
5.10.265 through 5.10.*Not affected
5.15.216 through 5.15.*Not affected
6.1.183 through 6.1.*Not affected
6.6.148 through 6.6.*Not affected
6.12.101 through 6.12.*Not affected
6.18.42 through 6.18.*Not affected
7.1.6 through 7.1.*Not affected
7.2 and laterNot affected

References

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