Linux Kernel up to 7.1.8 TCP Fast Open tcp_fastopen_create_child privileges management

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6.2	$0-$5k	1.28-

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.8 and classified as critical. This affects the function tcp_fastopen_create_child of the component TCP Fast Open. Executing a manipulation can lead to privileges management. This vulnerability appears as CVE-2026-74696. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.8. It has been declared as critical. This vulnerability affects the function tcp_fastopen_create_child of the component TCP Fast Open. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen accounting across reuseport migration A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through far more pending Fast Open requests than it was configured for. This only shows up with SO_REUSEPORT listener migration, where closing a listener hands its still-pending TFO children over to a surviving one. fastopenq.qlen is charged in tcp_fastopen_create_child() when the child is created and uncharged in reqsk_fastopen_remove() when the handshake completes. The uncharge follows rsk_listener of the request the child points at, and inet_reqsk_clone() has repointed the child at a new request owned by the new listener, so the ++ and the -- land on two different sockets. The new listener's qlen drifts negative and its limit no longer binds. Charge the new listener during migration, like reqsk_queue_migrated() already does for queue->young and queue->qlen.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-74696 since 08/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/22/2026). The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45 or 7.1.9 eliminates this vulnerability. Applying the patch e98f0d80b9cccb5f828425d2004f9686e7d1ae24/b6247e0f96bd825ffb2005257f6177b5e642dee6/585fc5247d14939a561056aa2addd9b7c2b1f670/6e10ee56524a26b250229ad348637825646ddb88/a66e869cf0c90c1e47ae75f72b6482acbfc808ff/d974618b2097453778389d385e3741629c40e0a3/a0ab2ba83e35159d81cec830a92e885ecf8139be is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.215
• 6.1.182
• 6.6.151
• 6.12.103
• 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
• 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

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: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
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: Privileges management
CWE: CWE-269 / CWE-266
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 5.15.216/6.1.183/6.6.152/6.12.104/6.18.45/7.1.9
Patch: e98f0d80b9cccb5f828425d2004f9686e7d1ae24/b6247e0f96bd825ffb2005257f6177b5e642dee6/585fc5247d14939a561056aa2addd9b7c2b1f670/6e10ee56524a26b250229ad348637825646ddb88/a66e869cf0c90c1e47ae75f72b6482acbfc808ff/d974618b2097453778389d385e3741629c40e0a3/a0ab2ba83e35159d81cec830a92e885ecf8139be

Timelineinfo

08/15/2026 CVE reserved
08/22/2026 +7 days Advisory disclosed
08/22/2026 +0 days VulDB entry created
08/22/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74696 (🔒)
GCVE (CVE): GCVE-0-2026-74696
GCVE (VulDB): GCVE-100-394468

Entryinfo

Created: 08/22/2026 18:54
Changes: 08/22/2026 18:54 (59)
Complete: 🔍
Cache ID: 216::103

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Discussion

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