# CVE-2026-48066: pam_usb: Thread-unsafe static pointer in log.c causes data race under concurrent PAM authentication


- **Severity:** Medium 5.7 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 27 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-qg76-57wq-mpv6

## What is CVE-2026-48066?

CVE-2026-48066 is a medium-severity vulnerability in mcdope pam_usb, published on 27 May 2026. 

### Official description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/log.c contains a process-wide static pointer that is written on every PAM invocation with the address of a stack-local variable. This violates the PAM re-entrancy requirement and creates a data race when the PAM stack is invoked concurrently from multiple threads. This vulnerability is fixed in 0.9.1.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-48066?


## How do I fix CVE-2026-48066?

No fix has been published for CVE-2026-48066 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-48066 being exploited?

There is no known exploitation of CVE-2026-48066 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48066 and fix it if it is affected.

What it is: CVE-2026-48066 is a medium-severity vulnerability in mcdope pam_usb, published on 27 May 2026. 
Exploitation: There is no known exploitation of CVE-2026-48066 in the wild and no public exploit code.

Affected product: mcdope pam_usb. 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-2026-48066/ (Markdown: https://insights.sbomify.com/CVE-2026-48066/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48066
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48066
- OSV: https://osv.dev/vulnerability/CVE-2026-48066

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48066/
Summaries are generated and may contain mistakes; the official description above is the record.