# CVE-2026-89552: params: fix charp corruption on allocation failure

> A local attacker with high privileges can trigger a kernel NULL pointer dereference and system crash by causing a memory allocation failure during parameter updates.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-100830, BELL-CVE-2026-89552, DEBIAN-CVE-2026-89552, GHSA-gmqc-x8hx-2ggc, UBUNTU-CVE-2026-89552

## What is CVE-2026-89552?

CVE-2026-89552 is a vulnerability in Linux, published on 11 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:

params: fix charp corruption on allocation failure

param_set_charp() stores charp parameters in allocated memory after slab is
available, and releases the previous value when the parameter is updated.

The previous value is released before the replacement allocation succeeds.
If kmalloc_parameter() fails, the setter returns -ENOMEM with the parameter
left as NULL.

Failing zswap's compressor update before zswap is initialized can later
trigger:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  RIP: 0010:strcmp+0x10/0x30
  Call Trace:
    zswap_setup+0x3b1/0x490
    zswap_enabled_param_set+0x5b/0xa0
    param_attr_store+0x93/0xe0
    module_attr_store+0x1c/0x30
    kernfs_fop_write_iter+0x116/0x1f0

Allocate and copy the replacement first, then replace the parameter value
only after allocation succeeds.

## Which versions are affected by CVE-2026-89552?


## How do I fix CVE-2026-89552?

Apply the vendor's patch.

## Is CVE-2026-89552 being exploited?

There is no known exploitation of CVE-2026-89552 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89552 and fix it if it is affected.

What it is: CVE-2026-89552 is a vulnerability in Linux, published on 11 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-2026-89552 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-2026-89552/ (Markdown: https://insights.sbomify.com/CVE-2026-89552/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89552
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89552
- OSV: https://osv.dev/vulnerability/CVE-2026-89552

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89552/
Summaries are generated and may contain mistakes; the official description above is the record.