# CVE-2020-28242: Denial of service in n/a

> A remote attacker can cause Asterisk to consume excessive memory and crash by triggering an infinite INVITE loop during outbound authentication challenges.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-28242, GHSA-q5gr-h5mj-hp63, UBUNTU-CVE-2020-28242

## What is CVE-2020-28242?

CVE-2020-28242 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 6 Nov 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An issue was discovered in Asterisk Open Source 13.x before 13.37.1, 16.x before 16.14.1, 17.x before 17.8.1, and 18.x before 18.0.1 and Certified Asterisk before 16.8-cert5. If Asterisk is challenged on an outbound INVITE and the nonce is changed in each response, Asterisk will continually send INVITEs in a loop. This causes Asterisk to consume more and more memory since the transaction will never terminate (even if the call is hung up), ultimately leading to a restart or shutdown of Asterisk. Outbound authentication must be configured on the endpoint for this to occur.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2020-28242?

It affects 4 products.


Products: Asterisk Certified Asterisk, Debian Debian Linux, Fedoraproject Fedora, Sangoma Asterisk.

## How do I fix CVE-2020-28242?

Upgrade to a fixed version.

## Is CVE-2020-28242 being exploited?

There is no known exploitation of CVE-2020-28242 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2022-21723](https://insights.sbomify.com/CVE-2022-21723/): Out-of-bounds read in multipart parsing in PJSIP (critical 9.1)
- [CVE-2022-23608](https://insights.sbomify.com/CVE-2022-23608/): Use after free in PJSIP (high 8.1)
- [CVE-2017-9358](https://insights.sbomify.com/CVE-2017-9358/): Denial of service in n/a (high 7.5)
- [CVE-2021-37706](https://insights.sbomify.com/CVE-2021-37706/): Potential integer underflow upon receiving STUN message in PJSIP (high 7.3)
- [CVE-2021-46837](https://insights.sbomify.com/CVE-2021-46837/): Null dereference in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-28242 and fix it if it is affected.

What it is: CVE-2020-28242 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 6 Nov 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-28242 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-2020-28242/ (Markdown: https://insights.sbomify.com/CVE-2020-28242/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-28242
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-28242
- OSV: https://osv.dev/vulnerability/CVE-2020-28242

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-28242/
Summaries are generated and may contain mistakes; the official description above is the record.