CVE-2026-68123

In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix GSO userspace truncation underflow OVS_ACTION_ATTR_TRUNC currently stores a delta from the original skb length in OVS_CB(skb)->cutlen. When a later userspace action segments a GSO skb, queue_gso_packets() reuses that delta for each smaller segment. A segment can then reach queue_userspace_packet() with cutlen greater than skb->len, underflowing the length passed to skb_zerocopy(). Store the maximum preserved length instead and bound each consumer against the current skb length. Use U32_MAX as the no-truncation sentinel so the value remains valid if skb geometry changes before a consumer handles it.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263
https://git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6
https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe
https://git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4
https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855
https://git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369
https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407
https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-10 13:19

Updated : 2026-08-19 17:20

NVD link : CVE-2026-68123

Mitre link : CVE-2026-68123

CVE.ORG link : CVE-2026-68123

JSON object : View

Products Affected

No product.

CWE

No CWE.

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When a later userspace action segments a\nGSO skb, queue_gso_packets() reuses that delta for each smaller segment.\nA segment can then reach queue_userspace_packet() with cutlen greater\nthan skb->len, underflowing the length passed to skb_zerocopy().\n\nStore the maximum preserved length instead and bound each consumer\nagainst the current skb length. Use U32_MAX as the no-truncation\nsentinel so the value remains valid if skb geometry changes before a\nconsumer handles it."}], "lastModified": "2026-08-19T17:20:29.700", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}