# CVE-2017-18120: Use after free in n/a

> A double-free vulnerability in gifsicle allows remote attackers to cause denial of service or potentially execute code via a crafted GIF file.

- **Severity:** High 7.8 (`CVSS:3.0/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 2 Feb 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-18120, GHSA-6f9j-p2gf-3f72, MGASA-2018-0280, UBUNTU-CVE-2017-18120

## What is CVE-2017-18120?

CVE-2017-18120 is a high-severity use after free vulnerability in n/a, published on 2 Feb 2018. 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

A double-free bug in the read_gif function in gifread.c in gifsicle 1.90 allows a remote attacker to cause a denial-of-service attack or unspecified other impact via a maliciously crafted file, because last_name is mishandled, a different vulnerability than CVE-2017-1000421.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2017-18120?

It affects 1 product.


Products: Lcdf Gifsicle.

## How do I fix CVE-2017-18120?

Upgrade to a fixed version.

## Is CVE-2017-18120 being exploited?

There is no known exploitation of CVE-2017-18120 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-46009](https://insights.sbomify.com/CVE-2023-46009/): Denial of service in n/a (high 7.8)
- [CVE-2023-36193](https://insights.sbomify.com/CVE-2023-36193/): Memory corruption in n/a (high 7.8)
- [CVE-2023-44821](https://insights.sbomify.com/CVE-2023-44821/): Denial of service in n/a (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-18120 and fix it if it is affected.

What it is: CVE-2017-18120 is a high-severity use after free vulnerability in n/a, published on 2 Feb 2018. 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-2017-18120 in the wild and no public exploit code.

Affected product: n/a. 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-2017-18120/ (Markdown: https://insights.sbomify.com/CVE-2017-18120/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-18120
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-18120
- OSV: https://osv.dev/vulnerability/CVE-2017-18120

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-18120/
Summaries are generated and may contain mistakes; the official description above is the record.