CVE-2026-23110
MediumCVSS 4.7Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
A race condition in the Linux kernel's SCSI layer can prevent the error handler from waking up when final commands complete concurrently. The issue stems from memory ordering problems and incorrect sequencing between counting busy commands and incrementing the failed counter. This can cause I/O on the SCSI host to become stuck in an error state.
Risk Assessment
The organization may experience a complete halt of I/O operations on SCSI devices, leading to data unavailability and potential loss of critical services. A local attacker could exploit this vulnerability to cause a denial of service (DoS) on the system.
Recommendation
Immediately update the Linux kernel to a version containing the fix, which adds a memory barrier on the error path and reorders calls in scsi_eh_inc_host_failed(). Upgrading to the latest stable kernel release is recommended.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: scsi: core: Wake up the error handler when final completions race against each other The fragile ordering between marking commands completed or failed so that the error handler only wakes when the last running command completes or times out has race conditions. These race conditions can cause the SCSI layer to fail to wake the error handler, leaving I/O through the SCSI host stuck as the error state cannot advance. First, there is an memory ordering issue within scsi_dec_host_busy(). The write which clears SCMD_STATE_INFLIGHT may be reordered with reads counting in scsi_host_busy(). While the local CPU will see its own write, reordering can allow other CPUs in scsi_dec_host_busy() or scsi_eh_inc_host_failed() to see a raised busy count, causing no CPU to see a host busy equal to the host_failed count. This race condition can be prevented with a memory barrier on the error path to force the write to be visible before counting host busy commands. Second, there is a general ordering issue with scsi_eh_inc_host_failed(). By counting busy commands before incrementing host_failed, it can race with a final command in scsi_dec_host_busy(), such that scsi_dec_host_busy() does not see host_failed incremented but scsi_eh_inc_host_failed() counts busy commands before SCMD_STATE_INFLIGHT is cleared by scsi_dec_host_busy(), resulting in neither waking the error handler task. This needs the call to scsi_host_busy() to be moved after host_failed is incremented to close the race condition.