Linux Kernel up to 7.2-rc2 f_fs kernel/workqueue.c ffs_fs_kill_sb use after free

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4.0	$0-$5k	0.60

Summaryinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 7.2-rc2. This issue affects the function ffs_fs_kill_sb of the file kernel/workqueue.c of the component f_fs. Executing a manipulation can lead to use after free. This vulnerability is registered as CVE-2026-64594. The attack needs to be launched locally. No exploit is available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.2-rc2 and classified as problematic. This vulnerability affects the function ffs_fs_kill_sb of the file kernel/workqueue.c of the component f_fs. 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 availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: initialize reset_work at allocation time ffs_fs_kill_sb() unconditionally calls cancel_work_sync() on ffs->reset_work when a functionfs instance is unmounted: ffs_data_reset(ffs); cancel_work_sync(&ffs->reset_work); However ffs->reset_work is only ever initialized via INIT_WORK() in ffs_func_set_alt() and ffs_func_disable(), and only on the FFS_DEACTIVATED path. That state is reached solely by ffs_data_closed() when the instance is mounted with the "no_disconnect" option, so for the common case (no "no_disconnect", or mounted and unmounted without ever being deactivated) reset_work is never initialized. ffs_data_new() allocates the ffs_data with kzalloc_obj() and does not initialize reset_work, and ffs_data_reset()/ffs_data_clear() do not touch it either, so reset_work.func is left NULL. cancel_work_sync() on such a work then trips the WARN_ON(!work->func) guard in __flush_work(): WARNING: kernel/workqueue.c:4301 at __flush_work+0x330/0x360, CPU#3: umount Call trace: __flush_work cancel_work_sync ffs_fs_kill_sb [usb_f_fs] deactivate_locked_super deactivate_super cleanup_mnt __cleanup_mnt task_work_run exit_to_user_mode_loop el0_svc On older kernels cancel_work_sync() on a zero-initialized work struct was a silent no-op, which hid the missing initialization. Initialize reset_work once in ffs_data_new() so it is always valid for the lifetime of the ffs_data, and drop the now-redundant INIT_WORK() calls from the two deactivation paths.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-64594 since 07/19/2026. The exploitation appears to be easy. The attack needs to be approached locally. The exploitation requires an enhanced level of successful authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.4 or 7.2-rc3 eliminates this vulnerability. Applying the patch 7fe895e0a9651518c4fc082487da770ff9c14c7f/0de6ebbabfbbc9c28350283dc97d8a519d5c6dd7/cb19e54ebe9baf3c3243083ade65c937339ccb7b/d5631081be07f20e764d3cb5c98ac0a1004fba51/c36393b0d14e1e9783888f821ffe29381b8f46dc/69faa3779250df14f51d5084f938a99809546e52/ba1867999dbc4085e6d8c52ac5266005b8b2bf07/3137b243c93982fe3460335e12f9247739766e10 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.260
• 5.15.211
• 6.1.177
• 6.6.144
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
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• 6.12.90
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• 6.12.93
• 6.12.94
• 6.12.95
• 6.12.96
• 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
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• 6.18.13
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• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.2-rc1
• 7.2-rc2

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: 4.2
VulDB Meta Temp Score: 4.0

VulDB Base Score: 4.2
VulDB Temp Score: 4.0
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: Partially
Local: Yes
Remote: Partially

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 5.10.261/5.15.212/6.1.178/6.6.145/6.12.97/6.18.40/7.1.4/7.2-rc3
Patch: 7fe895e0a9651518c4fc082487da770ff9c14c7f/0de6ebbabfbbc9c28350283dc97d8a519d5c6dd7/cb19e54ebe9baf3c3243083ade65c937339ccb7b/d5631081be07f20e764d3cb5c98ac0a1004fba51/c36393b0d14e1e9783888f821ffe29381b8f46dc/69faa3779250df14f51d5084f938a99809546e52/ba1867999dbc4085e6d8c52ac5266005b8b2bf07/3137b243c93982fe3460335e12f9247739766e10

Timelineinfo

07/19/2026 CVE reserved
08/06/2026 +18 days Advisory disclosed
08/06/2026 +0 days VulDB entry created
08/06/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64594 (🔒)
GCVE (CVE): GCVE-0-2026-64594
GCVE (VulDB): GCVE-100-386500

Entryinfo

Created: 08/06/2026 09:43
Changes: 08/06/2026 09:43 (60)
Complete: 🔍
Cache ID: 216::103

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