# CVE-2021-39176: Missing Release of Memory after Effective Lifetime in detect-character-encoding

> Attackers can cause denial of service by exhausting memory through repeated calls to the detect-character-encoding library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 31 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-5rwj-j5m3-3chj

## What is CVE-2021-39176?

CVE-2021-39176 is a high-severity denial of service vulnerability in sonicdoe detect-character-encoding, published on 31 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

detect-character-encoding is a package for detecting character encoding using ICU. In detect-character-encoding v0.3.0 and earlier, allocated memory is not released. The problem has been patched in detect-character-encoding v0.3.1.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2021-39176?

2 open source packages ship an affected version, including detect-character-encoding. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `detect-character-encoding` | npm | All versions | 0.3.1 |
| `detect-character-encoding` | npm | All versions | 0.3.1 |

Products: Detect-Character-Encoding Project Detect-Character-Encoding.

## How do I fix CVE-2021-39176?

Upgrade detect-character-encoding to 0.3.1 or later.

## Is CVE-2021-39176 being exploited?

There is no known exploitation of CVE-2021-39176 in the wild and no public exploit code.

## Other vulnerabilities in sonicdoe detect-character-encoding

- [CVE-2021-39157](https://insights.sbomify.com/CVE-2021-39157/): Improper Handling of Exceptional Conditions in detect-character-encoding (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-39176 and fix it if it is affected.

What it is: CVE-2021-39176 is a high-severity denial of service vulnerability in sonicdoe detect-character-encoding, published on 31 Aug 2021. 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-2021-39176 in the wild and no public exploit code.

Affected packages and fixed versions:
- detect-character-encoding (npm): affected all versions; fixed in 0.3.1
- detect-character-encoding (npm): affected all versions; fixed in 0.3.1

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-2021-39176/ (Markdown: https://insights.sbomify.com/CVE-2021-39176/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-39176
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-39176
- OSV: https://osv.dev/vulnerability/CVE-2021-39176

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-39176/
Summaries are generated and may contain mistakes; the official description above is the record.