CVE-2026-80854

A flaw was found in the Linux kernel's f_tcm USB gadget module. A race condition can occur during the teardown of a Logical Unit Number (LUN) when it overlaps with a session removal. This timing issue can lead to a use-after-free vulnerability, causing the system to crash and resulting in a Denial of Service (DoS).

A lifetime race in usb gadget f_tcm can occur when the last LUN is unlinked while nexus removal is running at the same time. The port count may reach zero before core_dev_del_lun has drained active LUN references, allowing target_remove_session to free sess_cmd_map while an in flight usbg_cmd and its work item can still be accessed. This is a kernel use after free candidate and has been observed as a DEBUG_OBJECTS free active warning followed by a target core BUG or Oops. For the CVSS the PR:L is used in the paranoid score because reliable triggering may be possible for a local actor with delegated gadget or target configfs control, such as a reduced capability service account or container root, even though typical systems require administrator privileges. The issue is not network reachable. Impact is at least local denial of service via kernel crash and in the worst defensible case may allow confidentiality or integrity impact due to kernel memory corruption.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.