# CVE-2026-98019: bpf: mark a NULL call argument precise

> A flaw in the Linux kernel BPF verifier allows bypassing precision checks, potentially leading to privilege escalation for local attackers.

- **Severity:** Not scored
- **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 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104519, BELL-CVE-2026-98019, DEBIAN-CVE-2026-98019, GHSA-cgv7-rwvp-jx5m, UBUNTU-CVE-2026-98019

## What is CVE-2026-98019?

CVE-2026-98019 is a vulnerability in Linux, published on 25 Sep 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: mark a NULL call argument precise

check_func_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

check_helper_call() enforces second parameter of the
bpf_get_local_storage() to be zero, w/o marking the underlying scalar
register precise. Hence a checkpoint created on such a path would
prune against arbitrary scalar value.

Grouping these two into one patch, as they share the same fixes tag.

## Which versions are affected by CVE-2026-98019?


## How do I fix CVE-2026-98019?

Apply the vendor's patch.

## Is CVE-2026-98019 being exploited?

There is no known exploitation of CVE-2026-98019 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98019 and fix it if it is affected.

What it is: CVE-2026-98019 is a vulnerability in Linux, published on 25 Sep 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-2026-98019 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-2026-98019/ (Markdown: https://insights.sbomify.com/CVE-2026-98019/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98019
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98019
- OSV: https://osv.dev/vulnerability/CVE-2026-98019

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98019/
Summaries are generated and may contain mistakes; the official description above is the record.