# CVE-2021-41145: FreeSWITCH susceptible to Denial of Service via SIP flooding

> An unauthenticated attacker can crash FreeSWITCH by flooding it with SIP messages, causing memory exhaustion and denial of service.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:** 25 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2021-41145, GHSA-jvpq-23v4-gp3m

## What is CVE-2021-41145?

CVE-2021-41145 is a high-severity denial of service vulnerability in signalwire freeswitch, published on 25 Oct 2021. 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. FreeSWITCH prior to version 1.10.7 is susceptible to Denial of Service via SIP flooding. When flooding FreeSWITCH with SIP messages, it was observed that after a number of seconds the process was killed by the operating system due to memory exhaustion. By abusing this vulnerability, an attacker is able to crash any FreeSWITCH instance by flooding it with SIP messages, leading to Denial of Service. The attack does not require authentication and can be carried out over UDP, TCP or TLS. This issue was patched in version 1.10.7.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-41145?

It affects 1 product.


Products: Freeswitch Freeswitch.

## How do I fix CVE-2021-41145?

Upgrade to a fixed version.

## Is CVE-2021-41145 being exploited?

There is no known exploitation of CVE-2021-41145 in the wild and no public exploit code.

## 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-2026-45771](https://insights.sbomify.com/CVE-2026-45771/): Freeswitch Denial-of-Service in SIP PUBLISH Requests via XML Entity Expansion (high 7.5)
- [CVE-2026-49475](https://insights.sbomify.com/CVE-2026-49475/): FreeSWITCH: Out-of-bounds memory access in core STUN attribute parsing (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41145 and fix it if it is affected.

What it is: CVE-2021-41145 is a high-severity denial of service vulnerability in signalwire freeswitch, published on 25 Oct 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-2021-41145 in the wild and no public exploit code.

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-2021-41145/ (Markdown: https://insights.sbomify.com/CVE-2021-41145/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41145
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41145
- OSV: https://osv.dev/vulnerability/CVE-2021-41145

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41145/
Summaries are generated and may contain mistakes; the official description above is the record.