# CVE-2020-25690: Memory corruption in fontforge

> An out-of-bounds write in FontForge allows attackers to execute arbitrary code or crash the application via malicious SFD files.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Feb 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-8m73-qxc4-m26m, MGASA-2020-0405, OESA-2021-1104, RHSA-2020:4844, UBUNTU-CVE-2020-25690

## What is CVE-2020-25690?

CVE-2020-25690 is a high-severity memory corruption vulnerability in fontforge, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

An out-of-bounds write flaw was found in FontForge in versions before 20200314 while parsing SFD files containing certain LayerCount tokens. This flaw allows an attacker to manipulate the memory allocated on the heap, causing the application to crash or execute arbitrary code. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2020-25690?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fontforge` | Red Hat:enterprise_linux:8::crb | All versions | 0:20170731-15.el8 |
| `fontforge-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:20170731-15.el8 |
| `fontforge-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 0:20170731-15.el8 |

Products: Fontforge Fontforge.

## How do I fix CVE-2020-25690?

Upgrade to a fixed version.

## Is CVE-2020-25690 being exploited?

There is no known exploitation of CVE-2020-25690 in the wild and no public exploit code.

## Other vulnerabilities in fontforge

- [CVE-2019-15785](https://insights.sbomify.com/CVE-2019-15785/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-15269](https://insights.sbomify.com/CVE-2025-15269/): FontForge SFD File Parsing Use-After-Free Remote Code Execution Vulnerability (high 8.8)
- [CVE-2025-15270](https://insights.sbomify.com/CVE-2025-15270/): FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability (high 8.8)
- [CVE-2025-15271](https://insights.sbomify.com/CVE-2025-15271/): FontForge SFD File Parsing Improper Validation of Array Index Remote Code Execution Vulnerability (high 8.8)
- [CVE-2025-15272](https://insights.sbomify.com/CVE-2025-15272/): FontForge SFD File Parsing Heap-based Buffer Overflow Remote Code Execution Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25690 and fix it if it is affected.

What it is: CVE-2020-25690 is a high-severity memory corruption vulnerability in fontforge, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-25690 in the wild and no public exploit code.

Affected product: fontforge. 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-2020-25690/ (Markdown: https://insights.sbomify.com/CVE-2020-25690/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25690
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25690
- OSV: https://osv.dev/vulnerability/CVE-2020-25690

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-25690/
Summaries are generated and may contain mistakes; the official description above is the record.