# CVE-2026-64467: rust_binder: use a u64 stride when cleaning up the offsets array

> A stride mismatch in the Linux kernel's Rust binder driver causes refcount underflows on 32-bit systems, leading to potential denial of service.

- **Severity:** High 8.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-64467, DEBIAN-CVE-2026-64467, GHSA-jcch-xvf6-72qc, ROOT-OS-UBUNTU-2204-CVE-2026-64467, UBUNTU-CVE-2026-64467

## What is CVE-2026-64467?

CVE-2026-64467 is a high-severity vulnerability in Linux, published on 25 Jul 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:

rust_binder: use a u64 stride when cleaning up the offsets array

Allocation's Drop walks the offsets array (binder_size_t = u64 entries),
cleaning up the objects, but it used usize instead of u64 for both the
stride and the per-entry read.

On 64-bit kernels (usize == u64) this is harmless, but on 32-bit kernels
it walks the 8-byte entries in 4-byte steps, iterating an N-entry array
2N times, and reads the always-zero high word as offset 0, cleaning up
the object at offset 0 N extra times. As a result the referenced node or
handle ends up with a lower reference count than it actually has (a
refcount over-decrement), and binder's reference accounting is corrupted;
for example, the owner can be notified of a strong reference release
(BR_RELEASE) even though references still remain.

Change the stride to u64, and read each entry as a u64, narrowing it to
usize with try_into().

On 32-bit ARM, when this over-decrement would drive a count below zero,
the driver's existing refcount guard refuses it and fires:

  rust_binder: Failure: refcount underflow!

## Which versions are affected by CVE-2026-64467?


## How do I fix CVE-2026-64467?

Apply the vendor's patch.

## Is CVE-2026-64467 being exploited?

There is no known exploitation of CVE-2026-64467 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64467 and fix it if it is affected.

What it is: CVE-2026-64467 is a high-severity vulnerability in Linux, published on 25 Jul 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-2026-64467 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-2026-64467/ (Markdown: https://insights.sbomify.com/CVE-2026-64467/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64467
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64467
- OSV: https://osv.dev/vulnerability/CVE-2026-64467

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64467/
Summaries are generated and may contain mistakes; the official description above is the record.