# CVE-2024-27088: es5-ext Regular Expression Denial of Service in `function#copy` and `function#toStringTokens`

> Attackers can cause application stalls by passing functions with long names to es5-ext, requiring an upgrade to the patched version.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Feb 2024
- **Updated:** 9 Aug 2024
- **Also known as:** CLSA-2026-1773793041, CLSA-2026-1781139201, DEBIAN-CVE-2024-27088, GHSA-4gmj-3p3h-gm8h, MINI-4m88-hcrx-c9pf, MINI-7f4f-f768-4f3h, MINI-7wwm-cfmg-cc62, UBUNTU-CVE-2024-27088

## What is CVE-2024-27088?

CVE-2024-27088 is a denial of service vulnerability in medikoo es5-ext, published on 26 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

es5-ext contains ECMAScript 5 extensions. Passing functions with very long names or complex default argument names into `function#copy` or `function#toStringTokens` may cause the script to stall. The vulnerability is patched in v0.10.63.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2024-27088?

2 open source packages ship an affected version, including es5-ext. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `es5-ext` | npm | From 0.10.0 | 0.10.63 |
| `es5-ext` | npm | From 0.10.0 | 0.10.63 |

Products: Medikoo Es5-Ext.

## How do I fix CVE-2024-27088?

Upgrade es5-ext to 0.10.63 or later.

## Is CVE-2024-27088 being exploited?

There is no known exploitation of CVE-2024-27088 in the wild and no public exploit code.

Public exploit code:

- redos (github_poc): https://github.com/200101WhoAmI/CVE-2024-27088

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-27088 and fix it if it is affected.

What it is: CVE-2024-27088 is a denial of service vulnerability in medikoo es5-ext, published on 26 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-27088 in the wild and no public exploit code.

Affected packages and fixed versions:
- es5-ext (npm): affected from 0.10.0; fixed in 0.10.63
- es5-ext (npm): affected from 0.10.0; fixed in 0.10.63

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-2024-27088/ (Markdown: https://insights.sbomify.com/CVE-2024-27088/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-27088
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-27088
- OSV: https://osv.dev/vulnerability/CVE-2024-27088

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-27088/
Summaries are generated and may contain mistakes; the official description above is the record.