# CVE-2026-90250: bpf, cgroup: Fix storage null-ptr-deref after replacing prog

> A local attacker can cause a kernel panic via null pointer dereference in BPF cgroup storage when replacing programs.

- **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:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-102347, BELL-CVE-2026-90250, DEBIAN-CVE-2026-90250, GHSA-364x-ffh5-8mmx, UBUNTU-CVE-2026-90250

## What is CVE-2026-90250?

CVE-2026-90250 is a 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, cgroup: Fix storage null-ptr-deref after replacing prog

Syzkaller reported a storage null-ptr-deref issue after replacing prog.
This occurs in the following scenario:
1. prog A, an empty prog, is attached to a cgrp.
2. prog B uses BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE and calls the
   bpf_get_local_storage helper.
3. link_update is called to replace prog A with prog B.

The reason is that __cgroup_bpf_replace fails to alloc and assign the
required cgrp storage for the incoming replacement prog. Consequently,
the new prog inherits an uninit storage, leading to null-ptr-deref panic
when kick the new prog.

Fix this by rejecting a link update if new_prog's cgroup storage is
incompatible with link->prog.

## Which versions are affected by CVE-2026-90250?


## How do I fix CVE-2026-90250?

Apply the vendor's patch.

## Is CVE-2026-90250 being exploited?

There is no known exploitation of CVE-2026-90250 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90250 and fix it if it is affected.

What it is: CVE-2026-90250 is a 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-2026-90250 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-2026-90250/ (Markdown: https://insights.sbomify.com/CVE-2026-90250/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90250
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90250
- OSV: https://osv.dev/vulnerability/CVE-2026-90250

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90250/
Summaries are generated and may contain mistakes; the official description above is the record.