# CVE-2017-16137: Regular Expression Denial of Service in debug

> An attacker can cause a denial of service in the Node.js debug module by sending large untrusted input to the o formatter, blocking execution.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Jun 2018
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-43792, AZL-43819, AZL-44400, AZL-44772, CLSA-2026-1772928825, CLSA-2026-1773101693, CLSA-2026-1774225208, CLSA-2026-1776904642, CLSA-2026-1776904643, CLSA-2026-1776904644, CLSA-2026-1776904645, CLSA-2026-1787560902, CLSA-2026-1787561993, CLSA-2026-1787562139, CLSA-2026-1787562258, DEBIAN-CVE-2017-16137, GHSA-gxpj-cx7g-858c, MINI-527f-gxwf-8223, ROOT-APP-NPM-CVE-2017-16137, UBUNTU-CVE-2017-16137

## What is CVE-2017-16137?

CVE-2017-16137 is a medium-severity denial of service vulnerability in HackerOne debug node module, published on 7 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The debug module is vulnerable to regular expression denial of service when untrusted user input is passed into the o formatter. It takes around 50k characters to block for 2 seconds making this a low severity issue.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2017-16137?

8 open source packages ship an affected version, including debug. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `debug` | npm | All versions | 2.6.9 |
| `debug` | npm | All versions | 2.6.9 |
| `debug` | npm | From 3.0.0 | 3.1.0 |
| `debug` | npm | From 3.0.0 | 3.1.0 |
| `debug` | npm | From 3.2.0 | 3.2.7 |
| `debug` | npm | From 3.2.0 | 3.2.7 |
| `debug` | npm | From 4.0.0 | 4.3.1 |
| `debug` | npm | From 4.0.0 | 4.3.1 |

Products: Debug Project Debug.

## How do I fix CVE-2017-16137?

Upgrade debug to a fixed version for your release line: 2.6.9, 3.1.0, 3.2.7 or 4.3.1.

## Is CVE-2017-16137 being exploited?

There is no known exploitation of CVE-2017-16137 in the wild and no public exploit code.

## Other vulnerabilities in HackerOne debug node module

- [CVE-2017-20165](https://insights.sbomify.com/CVE-2017-20165/): debug-js debug node.js useColors redos (low 3.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-16137 and fix it if it is affected.

What it is: CVE-2017-16137 is a medium-severity denial of service vulnerability in HackerOne debug node module, published on 7 Jun 2018. 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-2017-16137 in the wild and no public exploit code.

Affected packages and fixed versions:
- debug (npm): affected all versions; fixed in 2.6.9
- debug (npm): affected all versions; fixed in 2.6.9
- debug (npm): affected from 3.0.0; fixed in 3.1.0
- debug (npm): affected from 3.0.0; fixed in 3.1.0
- debug (npm): affected from 3.2.0; fixed in 3.2.7
- debug (npm): affected from 3.2.0; fixed in 3.2.7
- debug (npm): affected from 4.0.0; fixed in 4.3.1
- debug (npm): affected from 4.0.0; fixed in 4.3.1

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-2017-16137/ (Markdown: https://insights.sbomify.com/CVE-2017-16137/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-16137
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-16137
- OSV: https://osv.dev/vulnerability/CVE-2017-16137

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-16137/
Summaries are generated and may contain mistakes; the official description above is the record.