# CVE-2026-98020: pds_core: fix cmd_regs access racing BAR unmap on reset

> A race condition in the pds_core driver allows unmapping memory during firmware updates, potentially causing a kernel crash or arbitrary code execution.

- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104229, BELL-CVE-2026-98020, DEBIAN-CVE-2026-98020, GHSA-qm2m-cwg6-99v6, UBUNTU-CVE-2026-98020

## What is CVE-2026-98020?

CVE-2026-98020 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:

pds_core: fix cmd_regs access racing BAR unmap on reset

pdsc_reset_prepare() and pdsc_reset_done()'s pdsc_map_bars() error path
clear/iounmap cmd_regs without devcmd_lock, and
pdsc_legacy_firmware_update()'s download loop derefs cmd_regs after
dropping and retaking the lock without re-checking. An FLR concurrent
with a devlink flash can unmap cmd_regs under an in-flight devcmd,
causing a NULL deref or a write to unmapped MMIO.

Take devcmd_lock across the BAR unmap/remap, and re-check cmd_regs in
the download loop. Only the PF maps cmd_regs and runs devcmd, so skip
the unmap on a VF, as pdsc_remove() and pdsc_reset_done() already do.

A reset that completes entirely within the unlocked window is not a
correctness problem for the image: the device clears its update session,
so a resumed download is rejected, and it verifies the staged image
before writing a flash slot, reporting PDS_RC_BAD_FW rather than
activating it.

pdsc_unmap_bars() also clears info_regs, intr_status and intr_ctrl. The
interrupt and start/stop readers of those are quiesced before the unmap
by pdsc_fw_down(), which frees the interrupts and tears down the queues.
The debugfs readers are not, since those files outlive a reset; that is
pre-existing and out of scope here.

## Which versions are affected by CVE-2026-98020?


## How do I fix CVE-2026-98020?

Apply the vendor's patch.

## Is CVE-2026-98020 being exploited?

There is no known exploitation of CVE-2026-98020 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98020 and fix it if it is affected.

What it is: CVE-2026-98020 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-2026-98020 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-2026-98020/ (Markdown: https://insights.sbomify.com/CVE-2026-98020/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98020
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98020
- OSV: https://osv.dev/vulnerability/CVE-2026-98020

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98020/
Summaries are generated and may contain mistakes; the official description above is the record.