Linux Kernel up to 7.2.5 virtio-net tun.c buffer overflow

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-$25k0.00

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.2.5. This affects an unknown function of the file tools/testing/selftests/net/tun.c of the component virtio-net. Executing a manipulation can lead to buffer overflow. This vulnerability is handled as CVE-2026-90063. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.5. It has been declared as very critical. This vulnerability affects an unknown function of the file tools/testing/selftests/net/tun.c of the component virtio-net. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: virtio-net: Ensure that TCP packets don't overflow gso_segs The user can specify any gso_size in a packet crafted with an AF_PACKET PACKET_VNET_HDR socket, even smaller than TCP_MIN_GSO_SIZE = 8. At the same time, GSO_MAX_SIZE = 8 * GSO_MAX_SEGS = 8 * 65535. When the user crafts a packet with gso_size < 8, there is a risk for partial GSO to overflow the 16-bit gso_segs field when dividing the SKB length by gso_size. Adjust gso_size of TCP packets to be at least TCP_MIN_GSO_SIZE = 8. Keep gso_size of UDP GSO packets, as gso_size=1 is valid and explicitly tested at tools/testing/selftests/net/tun.c:649.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-90063 since 09/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch d3d111fe809773edbb4ae121e36253b7d683509a/8f6667a081887c2b59c6f3dd86c1789ada563762/339f47ae04dcc6b5a730dd6bc70dddc8937c3260/29bd12c7c5f9d6cf855b87bace18f71e9607f9e8/0e5ed3b98d1d8d251acfdccfeaa607453ad12954/75c271c48f483af678e514734e10b2452410e08c/c27c449d455aafd9018a3cbab150f1c42c87923f is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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Version

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
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 5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: d3d111fe809773edbb4ae121e36253b7d683509a/8f6667a081887c2b59c6f3dd86c1789ada563762/339f47ae04dcc6b5a730dd6bc70dddc8937c3260/29bd12c7c5f9d6cf855b87bace18f71e9607f9e8/0e5ed3b98d1d8d251acfdccfeaa607453ad12954/75c271c48f483af678e514734e10b2452410e08c/c27c449d455aafd9018a3cbab150f1c42c87923f

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90063 (🔒)
GCVE (CVE): GCVE-0-2026-90063
GCVE (VulDB): GCVE-100-406546

Entryinfo

Created: 09/17/2026 18:35
Changes: 09/17/2026 18:35 (59)
Complete: 🔍
Cache ID: 216::103

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