# CVE-2018-20623: Use after free in n/a

> A use-after-free vulnerability in GNU Binutils allows attackers to execute arbitrary code or cause a denial of service via a crafted ELF file.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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:** 31 Dec 2018
- **Updated:** 6 May 2025
- **Also known as:** DEBIAN-CVE-2018-20623, GHSA-m2v7-7635-wpj6, UBUNTU-CVE-2018-20623

## What is CVE-2018-20623?

CVE-2018-20623 is a medium-severity use after free vulnerability in Gnu Binutils, published on 31 Dec 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

In GNU Binutils 2.31.1, there is a use-after-free in the error function in elfcomm.c when called from the process_archive function in readelf.c via a crafted ELF file.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2018-20623?

It affects 1 product.


Products: Gnu Binutils.

## How do I fix CVE-2018-20623?

Apply the vendor's patch.

## Is CVE-2018-20623 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-20623 exists.

## Other vulnerabilities in Gnu Binutils

- [CVE-2017-7614](https://insights.sbomify.com/CVE-2017-7614/): Null dereference in n/a (critical 9.8)
- [CVE-2014-9939](https://insights.sbomify.com/CVE-2014-9939/): Memory corruption in n/a (critical 9.8)
- [CVE-2017-7226](https://insights.sbomify.com/CVE-2017-7226/): Information disclosure in n/a (critical 9.1)
- [CVE-2017-6969](https://insights.sbomify.com/CVE-2017-6969/): Information disclosure in n/a (critical 9.1)
- [CVE-2020-19726](https://insights.sbomify.com/CVE-2020-19726/): Denial of service in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20623 and fix it if it is affected.

What it is: CVE-2018-20623 is a medium-severity use after free vulnerability in Gnu Binutils, published on 31 Dec 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-20623 exists.

Affected product: Gnu Binutils. 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-2018-20623/ (Markdown: https://insights.sbomify.com/CVE-2018-20623/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20623
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20623
- OSV: https://osv.dev/vulnerability/CVE-2018-20623

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20623/
Summaries are generated and may contain mistakes; the official description above is the record.