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CVE-2026-68123

Unknown

Last modified

CVE-2026-68123 is a vulnerability of currently unknown severity. 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.

Description

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1, < a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855; >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1, < fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc; >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1, < 100a23b1613e9218e0af654ef102352c713f0263; >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1, < ea85dbcbe8d4056ecb54352f97743d138ea4c407; >= f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1, < 4032f8ed10fcb84d41c508dfb04be96589f78dfe
LinuxLinux4.8

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is 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.
How severe is CVE-2026-68123?
Severity scoring for CVE-2026-68123 is pending analysis.
How do I fix CVE-2026-68123?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST