# CVE-2026-116569: FreeSWITCH MSRP buffer underflow in msrp_parse_buffer

Source: https://junglewise.ai/threats/cve-2026-116569-freeswitch-is-a-software-defined-telecom-stack-enabling-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-05  
License: CC BY 4.0 with a link back

CVE-2026-116569 · Severity: high · CVSS 7.5 · Published 2026-11-05

FreeSWITCH is a telecommunications software platform that routes calls and media streams. An unauthenticated attacker on the network can trigger a memory corruption bug in the MSRP (Message Session Relay Protocol) parser by sending a specially crafted message, causing FreeSWITCH to crash and drop all active calls. The vulnerability is only exploitable on systems with the MSRP listener enabled.

Technologies: [SignalWire FreeSWITCH](https://junglewise.ai/threats/technologies/freeswitch). Vendors: [SignalWire](https://junglewise.ai/threats/vendors/signalwire).

## Quick answers

**Is CVE-2026-116569 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116569 being exploited in the wild.

**How severe is CVE-2026-116569?** High severity, with a CVSS score of 7.5, published 5 November 2026.

**Which products and versions are affected?** SignalWire FreeSWITCH before 1.11.2.

**Is there a fix for CVE-2026-116569?** Yes: fixed in 1.11.2. Until then: The MSRP listener is disabled by default in msrp.conf.xml; deployments that do not explicitly enable MSRP on a TCP or TLS port are unaffected. If MSRP is required, restrict network access to the MSRP port to trusted peers only until an upgrade is possible. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116569 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-116569?** Check whether you run SignalWire FreeSWITCH at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.11.2

The MSRP listener is disabled by default in msrp.conf.xml; deployments that do not explicitly enable MSRP on a TCP or TLS port are unaffected. If MSRP is required, restrict network access to the MSRP port to trusted peers only until an upgrade is possible.

## Technical details

The msrp_parse_buffer() function in FreeSWITCH performs unsigned integer arithmetic on a peer-controlled segment length without bounds checking, leading to integer underflow when subtracting delimiter framing. The wrapped result near SIZE_MAX is then passed to switch_msrp_msg_set_payload() as both an allocation size and memcpy length, and related pointer arithmetic can read before the receive buffer. The vulnerability requires MSRP to be enabled on a TCP or TLS port and affects authentication-free parsing of the initial framing.

## Affected products

- SignalWire FreeSWITCH before 1.11.2

## Timeline

- 2026-11-05: disclosed

## References

- [https://github.com/signalwire/freeswitch/commit/349f55ff546ab365f026eb254965af98232f81a9](https://github.com/signalwire/freeswitch/commit/349f55ff546ab365f026eb254965af98232f81a9)
- [https://github.com/signalwire/freeswitch/releases/tag/v1.11.2](https://github.com/signalwire/freeswitch/releases/tag/v1.11.2)

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