Linux Kernel up to 7.2.2 f_tcm tcm_usbg_drop_nexus use after free

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	$5k-$25k	0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.2 and classified as very critical. Impacted is the function tcm_usbg_drop_nexus of the component f_tcm. Executing a manipulation can lead to use after free. This vulnerability is registered as CVE-2026-80854. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.2.2 and classified as very critical. This vulnerability affects the function tcm_usbg_drop_nexus of the component f_tcm. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: keep port count until LUN teardown completes tcm_usbg_drop_nexus() permits session removal once tpg_port_count reaches zero. However, usbg_port_unlink() currently decrements that count from the fabric_pre_unlink() callback, before core_dev_del_lun() waits for active se_lun references to drain. If removal of the last LUN races a nexus removal, the latter can observe a zero port count and call target_remove_session(). This frees sess_cmd_map while an in-flight struct usbg_cmd, including its work item, can still be accessed. Overlapping the last-LUN unlink with nexus removal reproduces this lifetime violation as a DEBUG_OBJECTS "free active" warning for usbg_cmd_work, followed by a target-core BUG/Oops. The generic target-core unlink path has no callback after core_dev_del_lun() completes. Add an optional fabric_post_unlink() callback and use it for the f_tcm port count. The count now remains nonzero until core_dev_del_lun() has finished draining active LUN references, preventing nexus removal from freeing the session during command completion.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-80854 since 08/26/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/04/2026).

Upgrading to version 5.10.269, 5.15.220, 6.1.187, 6.6.156, 6.12.108, 6.18.49, 7.1.13, 7.2.3 or 7.3-rc1 eliminates this vulnerability. Applying the patch c494c5562ca69b61a82f566e3b87a445d2c28929/c1f359d9a5efed458946063de65ddbeaacc4f165/178f59a0bccd3f66cdfa5184310f31a58b7257c4/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b/2efbfd42441d3ef8137aff2d59e9835e1d5ae780/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95/bbd6aa311a9f4dd17822c7557451458d3d2e980b/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa/c39d0916da47d94909391876c9e5bd429ea7b1b9 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.268
• 5.15.219
• 6.1.186
• 6.6.155
• 6.12.107
• 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
• 6.18.46
• 6.18.47
• 6.18.48
• 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
• 7.1.10
• 7.1.11
• 7.1.12
• 7.2.0
• 7.2.1
• 7.2.2

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: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
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: Use after free
CWE: CWE-416 / CWE-119
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 5.10.269/5.15.220/6.1.187/6.6.156/6.12.108/6.18.49/7.1.13/7.2.3/7.3-rc1
Patch: c494c5562ca69b61a82f566e3b87a445d2c28929/c1f359d9a5efed458946063de65ddbeaacc4f165/178f59a0bccd3f66cdfa5184310f31a58b7257c4/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b/2efbfd42441d3ef8137aff2d59e9835e1d5ae780/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95/bbd6aa311a9f4dd17822c7557451458d3d2e980b/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa/c39d0916da47d94909391876c9e5bd429ea7b1b9

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-2026-80854 (🔒)
GCVE (CVE): GCVE-0-2026-80854
GCVE (VulDB): GCVE-100-398920

Entryinfo

Created: 09/04/2026 18:18
Changes: 09/04/2026 18:18 (59)
Complete: 🔍
Cache ID: 216::103

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