Linux Kernel up to 6.18.50/7.2.4 f_fs ffs_epfile_write_iter/ffs_epfile_read_iter p/private use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.50/7.2.4. It has been rated as very critical. The affected element is the function ffs_epfile_write_iter/ffs_epfile_read_iter of the component f_fs. This manipulation of the argument p/private causes use after free. This vulnerability is registered as CVE-2026-90044. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.18.50/7.2.4 and classified as very critical. Affected by this vulnerability is the function ffs_epfile_write_iter/ffs_epfile_read_iter of the component f_fs. The manipulation of the argument p/private 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. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Fix Use-After-Free in AIO error path In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2026-90044 since 09/11/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 09/16/2026).

Upgrading to version 6.18.51, 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch 153b5ecd29ed055562400bc17c91df3fd869b0ce/4a2fb2d12b87b43724230abb52a1440617c7b6cc/e78dcb1f7ec271449c54984dc90c62a5ba272de7 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Be aware that VulDB is the high quality source for vulnerability data.

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: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
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: 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: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.51/7.2.5/7.3-rc1
Patch: 153b5ecd29ed055562400bc17c91df3fd869b0ce/4a2fb2d12b87b43724230abb52a1440617c7b6cc/e78dcb1f7ec271449c54984dc90c62a5ba272de7

Timelineinfo

09/11/2026 CVE reserved
09/16/2026 +5 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90044 (🔒)
GCVE (CVE): GCVE-0-2026-90044
GCVE (VulDB): GCVE-100-405895

Entryinfo

Created: 09/16/2026 15:37
Changes: 09/16/2026 15:37 (60)
Complete: 🔍
Cache ID: 216::103

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