# CVE-2026-98376: bpf: Use array_map_meta_equal for percpu array inner map replacement

> A local attacker with BPF privileges can trigger an out-of-bounds read in the Linux kernel by replacing a percpu array inner map, potentially leaking memory or causing a crash.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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:** 9 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** BELL-CVE-2026-98376, DEBIAN-CVE-2026-98376, GHSA-69ch-wm32-w5g8, UBUNTU-CVE-2026-98376

## What is CVE-2026-98376?

CVE-2026-98376 is a high-severity memory corruption vulnerability in Linux, published on 9 Oct 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: Use array_map_meta_equal for percpu array inner map replacement

percpu_array_map_ops.map_meta_equal points to the generic
bpf_map_meta_equal(), which does not compare max_entries.  When a
percpu array serves as an inner map, replacing it with one that has
fewer max_entries bypasses the check.  Since percpu_array_map_gen_lookup()
inlines the original template's index_mask as a JIT immediate, a lookup
on the replacement map can access pptrs[] out of bounds.

Point percpu_array_map_ops.map_meta_equal to array_map_meta_equal(),
which already enforces the max_entries equality check.

Add a selftest to verify that replacing a percpu array inner map with
a differently-sized one is rejected.

## Which versions are affected by CVE-2026-98376?


## How do I fix CVE-2026-98376?

Apply the vendor's patch.

## Is CVE-2026-98376 being exploited?

There is no known exploitation of CVE-2026-98376 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98376 and fix it if it is affected.

What it is: CVE-2026-98376 is a high-severity memory corruption vulnerability in Linux, published on 9 Oct 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-2026-98376 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-2026-98376/ (Markdown: https://insights.sbomify.com/CVE-2026-98376/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98376
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98376
- OSV: https://osv.dev/vulnerability/CVE-2026-98376

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98376/
Summaries are generated and may contain mistakes; the official description above is the record.