# CVE-2026-64353: bpf: Keep dynamic inner array lookups nullable

> A Linux kernel BPF verifier flaw allows incorrect nullness elision for dynamic inner map lookups, potentially leading to undefined behavior or crashes.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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-2026-64353, DEBIAN-CVE-2026-64353, GHSA-rx38-5x73-p7h9, ROOT-OS-UBUNTU-2204-CVE-2026-64353, UBUNTU-CVE-2026-64353

## What is CVE-2026-64353?

CVE-2026-64353 is a medium-severity vulnerability in Linux kernel, 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:

bpf: Keep dynamic inner array lookups nullable

An ARRAY_OF_MAPS can use an array created with BPF_F_INNER_MAP as its
inner map template. A concrete inner array with a different max_entries
value can then replace the template.

After a successful outer map lookup, the verifier represents the
resulting map pointer using the inner map template. Const-key lookup
nullness elision consequently uses the template max_entries even though
the runtime helper uses the concrete inner map max_entries.

Do not elide lookup result nullness for maps marked with BPF_F_INNER_MAP,
because the template max_entries does not prove that the key is in bounds
for the concrete runtime map.

## Which versions are affected by CVE-2026-64353?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64353?

Apply the vendor's patch.

## Is CVE-2026-64353 being exploited?

There is no known exploitation of CVE-2026-64353 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64353 and fix it if it is affected.

What it is: CVE-2026-64353 is a medium-severity vulnerability in Linux kernel, 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-2026-64353 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-64353/ (Markdown: https://insights.sbomify.com/CVE-2026-64353/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64353
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64353
- OSV: https://osv.dev/vulnerability/CVE-2026-64353

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64353/
Summaries are generated and may contain mistakes; the official description above is the record.