# CVE-2021-39826: Adobe Digital Editions Command Execution Vulnerability

> An authenticated attacker can execute arbitrary commands by tricking a user into opening a maliciously crafted .epub file in Adobe Digital Editions.

- **Severity:** High 8.6 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 27 Sep 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-42gw-xghc-5vpq

## What is CVE-2021-39826?

CVE-2021-39826 is a high-severity command injection vulnerability in Adobe Digital Editions, published on 27 Sep 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Adobe Digital Editions 4.5.11.187646 (and earlier) are affected by an arbitrary command execution vulnerability. An authenticated attacker could leverage this vulnerability to execute arbitrary commands. User interaction is required to abuse this vulnerability in that a user must open a maliciously crafted .epub file.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-39826?

It affects 1 product.


Products: Adobe Digital Editions.

## How do I fix CVE-2021-39826?

No fix has been published for CVE-2021-39826 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-39826 being exploited?

There is no known exploitation of CVE-2021-39826 in the wild and no public exploit code.

## Other vulnerabilities in Adobe Digital Editions

- [CVE-2017-3088](https://insights.sbomify.com/CVE-2017-3088/): Memory corruption in Adobe Digital Editions 4.5.4 and earlier. (critical 10.0)
- [CVE-2014-0494](https://insights.sbomify.com/CVE-2014-0494/): Memory corruption in n/a (critical 10.0)
- [CVE-2013-1377](https://insights.sbomify.com/CVE-2013-1377/): Memory corruption in n/a (critical 10.0)
- [CVE-2020-3760](https://insights.sbomify.com/CVE-2020-3760/): Command injection in Adobe Digital Editions (critical 9.8)
- [CVE-2019-7095](https://insights.sbomify.com/CVE-2019-7095/): Memory corruption in Adobe Digital Editions (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39826 and fix it if it is affected.

What it is: CVE-2021-39826 is a high-severity command injection vulnerability in Adobe Digital Editions, published on 27 Sep 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-39826 in the wild and no public exploit code.

Affected product: Adobe Digital Editions. 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-2021-39826/ (Markdown: https://insights.sbomify.com/CVE-2021-39826/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39826
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39826
- OSV: https://osv.dev/vulnerability/CVE-2021-39826

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39826/
Summaries are generated and may contain mistakes; the official description above is the record.