# CVE-2023-40019: Denial of service in freeswitch

> Authorized users can crash FreeSWITCH by sending re-INVITE messages with duplicate codec names, causing internal array overflows.

- **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:** No
- **Published:** 15 Sep 2023
- **Updated:** 25 Sep 2024
- **Also known as:** GHSA-gjj5-79p2-9g3q

## What is CVE-2023-40019?

CVE-2023-40019 is a high-severity denial of service vulnerability in signalwire freeswitch, published on 15 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to version 1.10.10, FreeSWITCH allows authorized users to cause a denial of service attack by sending re-INVITE with SDP containing duplicate codec names. When a call in FreeSWITCH completes codec negotiation, the `codec_string` channel variable is set with the result of the negotiation. On a subsequent re-negotiation, if an SDP is offered that contains codecs with the same names but with different formats, there may be too many codec matches detected by FreeSWITCH leading to overflows of its internal arrays. By abusing this vulnerability, an attacker is able to corrupt stack of FreeSWITCH leading to an undefined behavior of the system or simply crash it. Version 1.10.10 contains a patch for this issue.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2023-40019?

It affects 1 product.


Products: Freeswitch Freeswitch.

## How do I fix CVE-2023-40019?

No fix has been published for CVE-2023-40019 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-40019 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-40019 exists.

## Other vulnerabilities in signalwire freeswitch

- [CVE-2026-49841](https://insights.sbomify.com/CVE-2026-49841/): FreeSWITCH: Pre-authentication heap buffer overflow in `mod_verto` HTTP POST body read (critical 9.8)
- [CVE-2019-19492](https://insights.sbomify.com/CVE-2019-19492/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2026-49840](https://insights.sbomify.com/CVE-2026-49840/): FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing (critical 9.1)
- [CVE-2021-41145](https://insights.sbomify.com/CVE-2021-41145/): FreeSWITCH susceptible to Denial of Service via SIP flooding (high 8.6)
- [CVE-2026-45771](https://insights.sbomify.com/CVE-2026-45771/): Freeswitch Denial-of-Service in SIP PUBLISH Requests via XML Entity Expansion (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-40019 and fix it if it is affected.

What it is: CVE-2023-40019 is a high-severity denial of service vulnerability in signalwire freeswitch, published on 15 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-40019 exists.

Affected product: signalwire freeswitch. 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-2023-40019/ (Markdown: https://insights.sbomify.com/CVE-2023-40019/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-40019
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-40019
- OSV: https://osv.dev/vulnerability/CVE-2023-40019

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-40019/
Summaries are generated and may contain mistakes; the official description above is the record.