CVE-2026-22995
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2026-01-23

Last updated on: 2026-02-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ublk: fix use-after-free in ublk_partition_scan_work A race condition exists between the async partition scan work and device teardown that can lead to a use-after-free of ub->ub_disk: 1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk() 2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does: - del_gendisk(ub->ub_disk) - ublk_detach_disk() sets ub->ub_disk = NULL - put_disk() which may free the disk 3. The worker ublk_partition_scan_work() then dereferences ub->ub_disk leading to UAF Fix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold a reference to the disk during the partition scan. The spinlock in ublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker either gets a valid reference or sees NULL and exits early. Also change flush_work() to cancel_work_sync() to avoid running the partition scan work unnecessarily when the disk is already detached.
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Meta Information
Published
2026-01-23
Last Modified
2026-02-26
Generated
2026-06-16
AI Q&A
2026-01-23
EPSS Evaluated
2026-06-15
NVD
CVE-2026-22995
EUVD
EUVD-2026-4282
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel 6.19
linux linux_kernel From 6.18.4 (inc) to 6.18.6 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

This vulnerability is a use-after-free (UAF) issue in the Linux kernel's ublk driver. It occurs due to a race condition between asynchronous partition scan work and device teardown. Specifically, after scheduling partition scan work, the device may be stopped and its disk freed, but the partition scan worker still tries to access the freed disk, leading to UAF. The fix involves holding a reference to the disk during the scan to prevent accessing freed memory and properly canceling work when the disk is detached.

Impact Analysis

This vulnerability can lead to use-after-free conditions, which may cause system instability, crashes, or potentially allow an attacker to execute arbitrary code or escalate privileges by exploiting the freed memory access in the kernel.

Mitigation Strategies

To mitigate this vulnerability, update your Linux kernel to a version that includes the fix for the use-after-free in ublk_partition_scan_work. The fix involves proper reference counting and synchronization to prevent the race condition. Until then, avoid operations that trigger partition scan work concurrently with device teardown. Specifically, ensure your system uses the patched kernel where ublk_get_disk()/ublk_put_disk() are used and flush_work() is replaced with cancel_work_sync() to prevent the issue.

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