# CVE-2020-35652: Denial of service in n/a

> A remote attacker can cause a denial of service in Asterisk by sending specially crafted SIP messages with tel-uri headers.

- **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:** 29 Jan 2021
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-35652, DEBIAN-CVE-2020-35652, GHSA-5jwx-hvg3-jjjv, UBUNTU-CVE-2020-35652

## What is CVE-2020-35652?

CVE-2020-35652 is a medium-severity denial of service vulnerability in Digium Asterisk, published on 29 Jan 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

An issue was discovered in res_pjsip_diversion.c in Sangoma Asterisk before 13.38.0, 14.x through 16.x before 16.15.0, 17.x before 17.9.0, and 18.x before 18.1.0. A crash can occur when a SIP message is received with a History-Info header that contains a tel-uri, or when a SIP 181 response is received that contains a tel-uri in the Diversion header.

## Which versions are affected by CVE-2020-35652?

It affects 1 product.


Products: Digium Asterisk.

## How do I fix CVE-2020-35652?

Upgrade to a fixed version.

## Is CVE-2020-35652 being exploited?

There is no known exploitation of CVE-2020-35652 in the wild and no public exploit code.

## Other vulnerabilities in Digium Asterisk

- [CVE-2017-14100](https://insights.sbomify.com/CVE-2017-14100/): Command injection in n/a (critical 9.8)
- [CVE-2014-8418](https://insights.sbomify.com/CVE-2014-8418/): Privilege escalation in n/a (critical 9.0)
- [CVE-2011-1599](https://insights.sbomify.com/CVE-2011-1599/): Missing authorization in n/a (critical 9.0)
- [CVE-2017-16671](https://insights.sbomify.com/CVE-2017-16671/): Memory corruption in n/a (high 8.8)
- [CVE-2017-7617](https://insights.sbomify.com/CVE-2017-7617/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-35652 and fix it if it is affected.

What it is: CVE-2020-35652 is a medium-severity denial of service vulnerability in Digium Asterisk, published on 29 Jan 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-35652 in the wild and no public exploit code.

Affected product: Digium Asterisk. 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-2020-35652/ (Markdown: https://insights.sbomify.com/CVE-2020-35652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35652
- OSV: https://osv.dev/vulnerability/CVE-2020-35652

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-35652/
Summaries are generated and may contain mistakes; the official description above is the record.