# CVE-2016-2338: Memory corruption in n/a

> A heap overflow in Ruby's Psych library allows attackers to execute arbitrary code via specially constructed objects.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** Yes
- **Published:** 14 Feb 2020
- **Updated:** 5 Aug 2024
- **Also known as:** CLSA-2025-1757699919, DLA-2158-1, GHSA-r46x-xjwr-8v2g

## What is CVE-2016-2338?

CVE-2016-2338 is a critical memory corruption vulnerability in Debian Debian Linux, published on 14 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exploitable heap overflow vulnerability exists in the Psych::Emitter start_document function of Ruby. In Psych::Emitter start_document function heap buffer "head" allocation is made based on tags array length. Specially constructed object passed as element of tags array can increase this array size after mentioned allocation and cause heap overflow.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2016-2338?

It affects 2 products.


Products: Debian Debian Linux, Ruby-Lang Ruby.

## How do I fix CVE-2016-2338?

Apply the vendor's patch.

## Is CVE-2016-2338 being exploited?

There is no known exploitation of CVE-2016-2338 in the wild and no public exploit code.

Public exploit code:

- CVE-2016-2338 Use-after-free nday full exploit (github_poc): https://github.com/SpiralBL0CK/CVE-2016-2338-nday

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-2338 and fix it if it is affected.

What it is: CVE-2016-2338 is a critical memory corruption vulnerability in Debian Debian Linux, published on 14 Feb 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-2338 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2016-2338/ (Markdown: https://insights.sbomify.com/CVE-2016-2338/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-2338
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-2338
- OSV: https://osv.dev/vulnerability/CVE-2016-2338

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-2338/
Summaries are generated and may contain mistakes; the official description above is the record.