# CVE-2026-93045: bpf: Reject arena frees below the arena base

> A flaw in the Linux kernel BPF arena allows out-of-bounds memory access, potentially enabling privilege escalation or code execution.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-93045, DEBIAN-CVE-2026-93045, GHSA-qfvw-mjm8-22x7, UBUNTU-CVE-2026-93045

## What is CVE-2026-93045?

CVE-2026-93045 is a high-severity memory corruption vulnerability in Linux, published on 17 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: Reject arena frees below the arena base

bpf_arena_free_pages() accepts scalar arena addresses. The runtime
masks the address to the low 32 bits and reconstructs a full user
address from the arena base before returning the range to the arena
free tree.

When the scalar value is below the low 32 bits of the arena base,
full_uaddr falls below user_vm_start. The existing upper-end clipping
then turns this into an out-of-range free-tree offset. A later
allocation can reuse that offset and return an address below the arena
mapping.

Reject such frees before computing the clipped range.

## Which versions are affected by CVE-2026-93045?


## How do I fix CVE-2026-93045?

Apply the vendor's patch.

## Is CVE-2026-93045 being exploited?

There is no known exploitation of CVE-2026-93045 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93045 and fix it if it is affected.

What it is: CVE-2026-93045 is a high-severity memory corruption vulnerability in Linux, published on 17 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-2026-93045 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-2026-93045/ (Markdown: https://insights.sbomify.com/CVE-2026-93045/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93045
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93045
- OSV: https://osv.dev/vulnerability/CVE-2026-93045

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93045/
Summaries are generated and may contain mistakes; the official description above is the record.