# CVE-2011-4126: Race condition in Calibre

> Unprivileged users can exploit a race condition in Calibre's Linux mount helper to mount arbitrary devices, potentially leading to privilege escalation.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Oct 2021
- **Updated:** 7 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-4126, GHSA-m85p-c5xr-7h82

## What is CVE-2011-4126?

CVE-2011-4126 is a high-severity vulnerability in Calibre, published on 27 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Race condition issues were found in Calibre at devices/linux_mount_helper.c allowing unprivileged users the ability to mount any device to anywhere.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2011-4126?

It affects 1 product.


Products: Calibre-Ebook Calibre.

## How do I fix CVE-2011-4126?

Apply the vendor's patch.

## Is CVE-2011-4126 being exploited?

There is no known exploitation of CVE-2011-4126 in the wild and no public exploit code.

## Other vulnerabilities in Calibre

- [CVE-2011-4124](https://insights.sbomify.com/CVE-2011-4124/): Command injection in Calibre (critical 9.8)
- [CVE-2011-4125](https://insights.sbomify.com/CVE-2011-4125/): Privilege escalation in Calibre (critical 9.8)
- [CVE-2026-26064](https://insights.sbomify.com/CVE-2026-26064/): calibre: Path Traversal Vulnerability Enables Arbitrary File Write and Remote Code Execution (critical 9.3)
- [CVE-2026-26065](https://insights.sbomify.com/CVE-2026-26065/): calibre: Path Traversal can Lead to Arbitrary File Write and Potential Code Execution (critical 9.3)
- [CVE-2026-25635](https://insights.sbomify.com/CVE-2026-25635/): calibre has a Path Traversal Leading to Arbitrary File Write and Potential Code Execution (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-4126 and fix it if it is affected.

What it is: CVE-2011-4126 is a high-severity vulnerability in Calibre, published on 27 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2011-4126 in the wild and no public exploit code.

Affected product: Calibre. 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-2011-4126/ (Markdown: https://insights.sbomify.com/CVE-2011-4126/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-4126
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-4126
- OSV: https://osv.dev/vulnerability/CVE-2011-4126

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-4126/
Summaries are generated and may contain mistakes; the official description above is the record.