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9.8
CRITICAL CVSS 3.1
CVE-2026-68123
openvswitch: fix GSO userspace truncation underflow
Overview
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.

Details
INFO

Published Date :

Aug. 10, 2026, 1:19 p.m.

Last Modified :

Aug. 17, 2026, 5:18 a.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-68123 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Fix GSO userspace truncation underflow in Linux kernel by storing max preserved length.
  • Update the Linux kernel to the latest version.
  • Apply the provided patch for the openvswitch fix.
  • Store maximum preserved length for GSO segments.
  • Bound consumers against the current skb length.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-68123.

URL Resource
https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263
https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe
https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855
https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407
https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-68123 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-68123 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-68123 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-68123 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 17, 2026

    Action Type Old Value New Value
    Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '100a23b1613e9218e0af654ef102352c713f0263', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'ea85dbcbe8d4056ecb54352f97743d138ea4c407', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '4032f8ed10fcb84d41c508dfb04be96589f78dfe', 'versionType': 'git'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc5', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '100a23b1613e9218e0af654ef102352c713f0263', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'ea85dbcbe8d4056ecb54352f97743d138ea4c407', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '4032f8ed10fcb84d41c508dfb04be96589f78dfe', 'versionType': 'git'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'affected'}]
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 13, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 10, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '100a23b1613e9218e0af654ef102352c713f0263', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': 'ea85dbcbe8d4056ecb54352f97743d138ea4c407', 'versionType': 'git'}, {'status': 'affected', 'version': 'f2a4d086ed4c588d32fe9b7aa67fead7280e7bf1', 'lessThan': '4032f8ed10fcb84d41c508dfb04be96589f78dfe', 'versionType': 'git'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc5', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/openvswitch/actions.c', 'net/openvswitch/datapath.c', 'net/openvswitch/datapath.h', 'net/openvswitch/vport.c'], 'defaultStatus': 'affected'}]
    Added 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.
    Added Reference https://git.kernel.org/stable/c/100a23b1613e9218e0af654ef102352c713f0263
    Added Reference https://git.kernel.org/stable/c/4032f8ed10fcb84d41c508dfb04be96589f78dfe
    Added Reference https://git.kernel.org/stable/c/a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855
    Added Reference https://git.kernel.org/stable/c/ea85dbcbe8d4056ecb54352f97743d138ea4c407
    Added Reference https://git.kernel.org/stable/c/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.8
Attack Vector
Attack Complexity
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Confidentiality Impact
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Availability Impact