CVE-2025-68288: usb: storage: Fix memory leak in USB bulk transport

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-16 · updated 2026-10-13

Description

In the Linux kernel, the following vulnerability has been resolved: usb: storage: Fix memory leak in USB bulk transport A kernel memory leak was identified by the 'ioctl_sg01' test from Linux Test Project (LTP). The following bytes were mainly observed: 0x53425355. When USB storage devices incorrectly skip the data phase with status data, the code extracts/validates the CSW from the sg buffer, but fails to clear it afterwards. This leaves status protocol data in srb's transfer buffer, such as the US_BULK_CS_SIGN 'USBS' signature observed here. Thus, this can lead to USB protocols leaks to user space through SCSI generic (/dev/sg*) interfaces, such as the one seen here when the LTP test requested 512 KiB. Fix the leak by zeroing the CSW data in srb's transfer buffer immediately after the validation of devices that skip data phase. Note: Differently from CVE-2018-1000204, which fixed a big leak by zero- ing pages at allocation time, this leak occurs after allocation, when USB protocol data is written to already-allocated sg pages.

Affected products

Linux kernel: from 3.16.58 before 3.17; from 3.18.110 before 3.19; from 4.4.133 before 4.5; from 4.9.103 before 4.10; from 4.14.44 before 4.15; from 4.16.12 before 4.17 — fixed in 3.17, 3.19, 4.10, 4.15, 4.17, 4.5

How to fix

Upgrade to a fixed version: Linux kernel 3.17, 3.19, 4.10, 4.15. Check the vendor advisory for mitigations.

References

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