openvswitch: fix GSO userspace truncation underflow

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68123
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 13:19:57 UTC
Updated2026-08-19 17:20:29 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.004970000 probability, percentile 0.405950000 (date 2026-08-19)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 50a6a85f3d6b1d22d8436848606cdef5d2c490b4 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 2623c48cc3a8da9a1886fd8f65c0e348f4406fd6 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 e211b081901ffca76674082c73eeaed53524c369 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 100a23b1613e9218e0af654ef102352c713f0263 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 ea85dbcbe8d4056ecb54352f97743d138ea4c407 git Not specified
CNA Linux Linux affected f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1 4032f8ed10fcb84d41c508dfb04be96589f78dfe git Not specified
CNA Linux Linux affected 4.8 Not specified
CNA Linux Linux unaffected 4.8 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.148 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.101 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.42 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.6 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e211b081901ffca76674082c73eeaed53524c369 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2623c48cc3a8da9a1886fd8f65c0e348f4406fd6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/50a6a85f3d6b1d22d8436848606cdef5d2c490b4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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