# CVE-2021-35985: Adobe Acrobat Pro DC PDFLibTool Null Pointer Dereference Bug

> An attacker can cause a denial of service in Adobe Acrobat Reader by tricking a user into opening a malicious file.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** No
- **Published:** 20 Aug 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-gxxf-959m-c3mf

## What is CVE-2021-35985?

CVE-2021-35985 is a medium-severity vulnerability in Adobe Acrobat Dc, published on 20 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Acrobat Reader DC versions 2021.005.20054 (and earlier), 2020.004.30005 (and earlier) and 2017.011.30197 (and earlier) are affected by a Null pointer dereference vulnerability. An unauthenticated attacker could leverage this vulnerability to achieve an application denial-of-service in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2021-35985?

It affects 2 products.


Products: Adobe Acrobat Dc, Adobe Acrobat Reader Dc.

## How do I fix CVE-2021-35985?

No fix has been published for CVE-2021-35985 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-35985 being exploited?

There is no known exploitation of CVE-2021-35985 in the wild and no public exploit code.

## Other vulnerabilities in Adobe Acrobat Dc

- [CVE-2018-4990](https://insights.sbomify.com/CVE-2018-4990/): Adobe Acrobat and Reader Double Free (high 8.8, exploited in the wild)
- [CVE-2020-9715](https://insights.sbomify.com/CVE-2020-9715/): Adobe Acrobat Use-After-Free (high 7.8, exploited in the wild)
- [CVE-2020-3792](https://insights.sbomify.com/CVE-2020-3792/): Use after free in Adobe Acrobat and Reader (critical 9.8)
- [CVE-2020-3793](https://insights.sbomify.com/CVE-2020-3793/): Use after free in Adobe Acrobat and Reader (critical 9.8)
- [CVE-2020-3795](https://insights.sbomify.com/CVE-2020-3795/): Memory corruption in Adobe Acrobat and Reader (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-35985 and fix it if it is affected.

What it is: CVE-2021-35985 is a medium-severity vulnerability in Adobe Acrobat Dc, published on 20 Aug 2021. 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-2021-35985 in the wild and no public exploit code.

Affected product: Adobe Acrobat Dc. 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-2021-35985/ (Markdown: https://insights.sbomify.com/CVE-2021-35985/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-35985
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-35985
- OSV: https://osv.dev/vulnerability/CVE-2021-35985

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-35985/
Summaries are generated and may contain mistakes; the official description above is the record.