# CVE-2026-74584: RDMA/bnxt_re: zero shared page before exposing to userspace

> Local users with RDMA device access can read uninitialized kernel memory due to a missing zeroing operation in the bnxt_re driver.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74584, DEBIAN-CVE-2026-74584, GHSA-j6vr-r53f-g3jf, UBUNTU-CVE-2026-74584

## What is CVE-2026-74584?

CVE-2026-74584 is a high-severity vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/bnxt_re: zero shared page before exposing to userspace

bnxt_re_alloc_ucontext() allocates uctx->shpg via
__get_free_page(GFP_KERNEL). The buddy allocator does not zero pages
without __GFP_ZERO, so the page contains stale kernel data from
whatever object most recently freed it.

The page is then mapped into userspace via vm_insert_page() under
BNXT_RE_MMAP_SH_PAGE in bnxt_re_mmap(). The driver only ever writes
4 bytes (a u32 AVID) at offset BNXT_RE_AVID_OFFT (0x10) inside
bnxt_re_create_ah(); the remaining 4092 bytes of the page are exposed
to userspace unsanitised, leaking kernel memory contents.

Any user with access to /dev/infiniband/uverbsX on a host with a
bnxt_re device (typically rdma group membership) can read this data
via a single mmap() at pgoff 0 after IB_USER_VERBS_CMD_GET_CONTEXT.

Other shared pages in the same file already use get_zeroed_page()
correctly:

  drivers/infiniband/hw/bnxt_re/ib_verbs.c
      srq->uctx_srq_page = (void *)get_zeroed_page(GFP_KERNEL);
      cq->uctx_cq_page  = (void *)get_zeroed_page(GFP_KERNEL);

uctx->shpg is the only outlier. Bring it in line with the existing
convention by switching to get_zeroed_page().

## Which versions are affected by CVE-2026-74584?


## How do I fix CVE-2026-74584?

Apply the vendor's patch.

## Is CVE-2026-74584 being exploited?

There is no known exploitation of CVE-2026-74584 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74584 and fix it if it is affected.

What it is: CVE-2026-74584 is a high-severity vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74584 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74584/ (Markdown: https://insights.sbomify.com/CVE-2026-74584/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74584
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74584
- OSV: https://osv.dev/vulnerability/CVE-2026-74584

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74584/
Summaries are generated and may contain mistakes; the official description above is the record.