# CVE-2021-32558: Denial of service in n/a

> A remote attacker can cause a denial of service in Asterisk by sending a crafted IAX2 packet with an unsupported media format.

- **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:** 27 Jul 2021
- **Updated:** 3 Aug 2024
- **Also known as:** ALPINE-CVE-2021-32558, DEBIAN-CVE-2021-32558, DLA-2729-1, GHSA-xhjf-mf8w-q63p, UBUNTU-CVE-2021-32558

## What is CVE-2021-32558?

CVE-2021-32558 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 27 Jul 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Sangoma Asterisk 13.x before 13.38.3, 16.x before 16.19.1, 17.x before 17.9.4, and 18.x before 18.5.1, and Certified Asterisk before 16.8-cert10. If the IAX2 channel driver receives a packet that contains an unsupported media format, a crash can occur.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2021-32558?

It affects 3 products.


Products: Debian Debian Linux, Digium Asterisk, Digium Certified Asterisk.

## How do I fix CVE-2021-32558?

Upgrade to a fixed version.

## Is CVE-2021-32558 being exploited?

There is no known exploitation of CVE-2021-32558 in the wild and no public exploit code.

## 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-2021-32558 and fix it if it is affected.

What it is: CVE-2021-32558 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 27 Jul 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-2021-32558 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-2021-32558/ (Markdown: https://insights.sbomify.com/CVE-2021-32558/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32558
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32558
- OSV: https://osv.dev/vulnerability/CVE-2021-32558

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32558/
Summaries are generated and may contain mistakes; the official description above is the record.