# CVE-2026-93206: PCI/proc: Use file_ns_capable() when checking config space read access

> An unprivileged process can read full PCI config space via procfs if a privileged process opens the file and passes the descriptor, bypassing access controls.

- **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:** 24 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-103940, BELL-CVE-2026-93206, DEBIAN-CVE-2026-93206, GHSA-fjc2-7frc-hj2c, UBUNTU-CVE-2026-93206

## What is CVE-2026-93206?

CVE-2026-93206 is a vulnerability in Linux, published on 24 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:

PCI/proc: Use file_ns_capable() when checking config space read access

proc_bus_pci_read() decides how much of the config space is readable based
on capable(CAP_SYS_ADMIN), which checks the credentials of the task calling
read(), not the credentials of the process that opened the file.

The sysfs equivalent, pci_read_config(), has checked the credentials of the
opening process since commit de139a339395 ("pci: check caps from sysfs file
open to read device dependent config space"), so a privileged process can
open the config space file and pass the file descriptor to an unprivileged
process (for example, a process running a KVM guest with an assigned
device), which can then read the entire config space.  The check was
subsequently routed through the LSM framework in commit 47970b1b2aa6 ("pci:
use security_capable() when checking capablities during config space read")
and converted to the dedicated helper in commit ab0fa82b2df9 ("pci-sysfs:
use proper file capability helper function").

Thus, the two interfaces check the same capability against different
credentials.  Checking the credentials of the task calling read() makes the
outcome depend on who reads rather than who opened, so the restriction is
bypassed whenever a more privileged process reads through the descriptor.
Checking the credentials recorded in file->f_cred settles the decision at
open() time and ties it to the file, where it cannot change with the
caller.

Use file_ns_capable() to check CAP_SYS_ADMIN against the credentials in
effect when the file was opened, bringing the procfs interface in line with
the sysfs behaviour.

As a result, a file descriptor opened by a privileged process and passed to
an unprivileged one now allows the entire config space to be read through
procfs, matching sysfs.

## Which versions are affected by CVE-2026-93206?


## How do I fix CVE-2026-93206?

Apply the vendor's patch.

## Is CVE-2026-93206 being exploited?

There is no known exploitation of CVE-2026-93206 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93206 and fix it if it is affected.

What it is: CVE-2026-93206 is a vulnerability in Linux, published on 24 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-2026-93206 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-2026-93206/ (Markdown: https://insights.sbomify.com/CVE-2026-93206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93206
- OSV: https://osv.dev/vulnerability/CVE-2026-93206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93206/
Summaries are generated and may contain mistakes; the official description above is the record.