Linux Kernel up to 7.1.9 Packet Socket packet_parse_headers uninitialized variable

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.5	$0-$5k	0.83

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel up to 7.1.9. This impacts the function packet_parse_headers of the component Packet Socket. Such manipulation leads to uninitialized variable. This vulnerability is uniquely identified as CVE-2026-80906. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.9. It has been rated as very critical. Affected by this issue is the function packet_parse_headers of the component Packet Socket. The manipulation with an unknown input leads to a uninitialized variable vulnerability. Using CWE to declare the problem leads to CWE-457. The code uses a variable that has not been initialized, leading to unpredictable or unintended results. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: packet: fix wrong transport_header when sending VLAN-tagged frame In packet_parse_headers(), when processing a VLAN-tagged frame, skb_set_network_header() is called to advance network_header past the VLAN tag to the inner protocol header. skb_probe_transport_header() is then called with skb->protocol still set to the outer VLAN EtherType (e.g. ETH_P_8021Q), while nhoff (derived from skb_network_offset()) already points past the VLAN tag to the inner protocol header. In __skb_flow_dissect(), proto is initialized to ETH_P_8021Q and nhoff points past the VLAN tag. When the dissector hits case ETH_P_8021Q, it reads a struct vlan_hdr at nhoff via __skb_header_pointer(), but that offset contains the inner protocol header (e.g. an IP header). The bytes are misinterpreted as a VLAN header, yielding a garbage encapsulated EtherType that matches no known protocol. The dissector returns false, so skb_probe_transport_header() never calls skb_set_transport_header(), leaving transport_header at its uninitialized sentinel value (~0U). Move skb_probe_transport_header() to before skb_set_network_header(). At the time skb_probe_transport_header() is called, network_header still points to the VLAN header, so nhoff correctly points to the VLAN header. The flow dissector can then parse the VLAN header, extract the inner EtherType, and advance nhoff to the inner protocol header, allowing transport_header to be set correctly.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-80906 since 08/26/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/04/2026).

Upgrading to version 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46 or 7.1.10 eliminates this vulnerability. Applying the patch a4b82de96d465ddb44bc931145c0fa80c4fe9c9c/fa86bc52ea8ba981f74f851fd61e2a3d3bc0feac/5479eb9b355f44745d7ccfe112386bd4f96eceea/e451e20adb869a983a21dda158625f024142e61f/6971cf319263d6a1b4096f9248aca9e57d77a1eb/f9297abbcaba760b7a7b9d63b839f607f738013e/6386a6ffa2efba2965ed8e4fa303582c0b76a215/01fdecc0480d916c799dbee584833a4a37e94d06 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.265
• 5.15.216
• 6.1.183
• 6.6.152
• 6.12.104
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.1.8
• 7.1.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Uninitialized variable
CWE: CWE-457 / CWE-453
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.266/5.15.217/6.1.184/6.6.153/6.12.105/6.18.46/7.1.10
Patch: a4b82de96d465ddb44bc931145c0fa80c4fe9c9c/fa86bc52ea8ba981f74f851fd61e2a3d3bc0feac/5479eb9b355f44745d7ccfe112386bd4f96eceea/e451e20adb869a983a21dda158625f024142e61f/6971cf319263d6a1b4096f9248aca9e57d77a1eb/f9297abbcaba760b7a7b9d63b839f607f738013e/6386a6ffa2efba2965ed8e4fa303582c0b76a215/01fdecc0480d916c799dbee584833a4a37e94d06

Timelineinfo

08/26/2026 CVE reserved
09/04/2026 +9 days Advisory disclosed
09/04/2026 +0 days VulDB entry created
09/04/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-80906 (🔒)
GCVE (CVE): GCVE-0-2026-80906
GCVE (VulDB): GCVE-100-399122

Entryinfo

Created: 09/04/2026 19:50
Changes: 09/04/2026 19:50 (59)
Complete: 🔍
Cache ID: 216::103

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