CVE-2026-116779: SignalWire FreeSwitch Code Injection Vulnerability

CVE-2026-116779 at a glance

CVE-2026-116779 is a critical-severity Code Injection vulnerability in SignalWire FreeSwitch, with a CVSS 3.1 base score of 9.8. NVD published it on 2026-11-06 and classifies the weakness as CWE-77, CWE-78 and CWE-749. CISA added it to the Known Exploited Vulnerabilities catalog on 2026-11-09; the federal remediation due date is 2026-11-12. FIRST EPSS puts the probability of exploitation activity in the next 30 days at 1.30% (percentile 70.6, scored 2026-11-09). NVD configuration data lists a fixed release for 1 product, for example freeswitch freeswitch 1.11.3. CVERadar maps 2 MITRE ATT&CK techniques across Initial Access and Execution, inferred from the CWE and the description. Its CVERadar threat level is 64/100.

What it is

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 1.11.3, sofia_presence_handle_sip_i_message() split the To user of an inbound SIP MESSAGE on a plus sign and treated the left side as a chat protocol selector. Selecting the api chat proto reached switch_api_execute(), allowing a peer whose MESSAGE was accepted to run FreeSWITCH API commands, including operating-system command sinks, with the daemon's privileges. Inbound chat is enabled on the stock internal and external profiles, and any authenticated profile account is sufficient; stock directory users without password material can also remove that barrier in affected configurations. The flaw permits configuration and credential disclosure, arbitrary call control, and command execution, and exploitation has been observed in the wild. This issue is fixed in version 1.11.3.

Exploitation evidence

First exploit evidence seen: 2026-11-09 (earliest date across the sources below).

Exploited in the wild

• CISA KEV: listed since 2026-11-09. CISA KEV listing

Public exploit code

GitHub proof-of-concept repositories below quality bar

2 public repositories from 2 accounts, first seen 2026-11-05.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: CISA KEV · nomi-sec/PoC-in-GitHub.

Patches, mitigations and detection

CISA required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. (source: CISA KEV)

Fixed versions

• freeswitch freeswitch: upgrade to 1.11.3 or later

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

• GitHub vendor advisory (github.com) (CISA KEV notes)
• GitHub patch (github.com) (Patch)
• GitHub patch (github.com) (Patch)
• GitHub release notes (github.com) (Release Notes)

MITRE ATT&CK mitigations for this chain

• M1048 Application Isolation and Sandboxing (for T1190) : Application isolation will limit what other processes and system features the exploited target can access.
• M1037 Filter Network Traffic (for T1190) : Restrict outbound network traffic from public-facing servers to prevent unauthorized connections from initiating communications with attacker-controlled infrastructure. While this may not prevent the initial exploitation, it limits the attacker's ability to verify and control the compromised server post-exploit, reduci
• M1030 Network Segmentation (for T1190) : Segment externally facing servers and services from the rest of the network with a DMZ or on separate hosting infrastructure.
• M1016 Vulnerability Scanning (for T1190) : Regularly scan externally facing systems for vulnerabilities and establish procedures to rapidly patch systems when critical vulnerabilities are discovered through scanning and through public disclosure.
• M1026 Privileged Account Management (for T1190, T1059) : Use least privilege for service accounts will limit what permissions the exploited process gets on the rest of the system.
• M1050 Exploit Protection (for T1190) : Web Application Firewalls may be used to limit exposure of applications to prevent exploit traffic from reaching the application.
• M1035 Limit Access to Resource Over Network (for T1190) : Ensure that all publicly exposed services are actually intended to be so, and restrict access to any that should only be available internally.
• M1051 Update Software (for T1190) : Update software regularly by employing patch management for externally exposed applications.
• M1033 Limit Software Installation (for T1059) : Prevent user installation of unrequired command and scripting interpreters.
• M1045 Code Signing (for T1059) : Where possible, only permit execution of signed scripts.

Detection Generic guidance

• Initial Access: Alert on unusual requests to the affected service (odd paths, oversized payloads, exploit strings) in WAF, reverse-proxy and application logs.
• Execution: Watch for the service process spawning shells or script interpreters (cmd.exe, powershell, sh, bash, python) via EDR process-tree rules.

Response checklist Generic guidance

1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.