Linux Kernel up to 7.2-rc4 openvswitch queue_userspace_packet cutlen off-by-one

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k2.23-

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4. This impacts the function queue_userspace_packet of the component openvswitch. The manipulation of the argument cutlen leads to off-by-one. This vulnerability is listed as CVE-2026-68123. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc4 and classified as very critical. This issue affects the function queue_userspace_packet of the component openvswitch. The manipulation of the argument cutlen with an unknown input leads to a off-by-one vulnerability. Using CWE to declare the problem leads to CWE-193. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-68123 since 07/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/10/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc/100a23b1613e9218e0af654ef102352c713f0263/ea85dbcbe8d4056ecb54352f97743d138ea4c407/4032f8ed10fcb84d41c508dfb04be96589f78dfe is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Off-by-one
CWE: CWE-193 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc5
Patch: a16eaaf7c0b0ccdef6166707d90ffbc6eebf6855/fbfa3ad2ad6f3a5624aba5211c46290fb98cc9dc/100a23b1613e9218e0af654ef102352c713f0263/ea85dbcbe8d4056ecb54352f97743d138ea4c407/4032f8ed10fcb84d41c508dfb04be96589f78dfe

Timelineinfo

07/30/2026 CVE reserved
08/10/2026 +11 days Advisory disclosed
08/10/2026 +0 days VulDB entry created
08/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-68123 (🔒)
GCVE (CVE): GCVE-0-2026-68123
GCVE (VulDB): GCVE-100-387473

Entryinfo

Created: 08/10/2026 15:03
Changes: 08/10/2026 15:03 (60)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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