CVE-2026-116779: SignalWire FreeSwitch flaw exploited in the wild, what we know

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.

• Severity: CRITICAL (CVSS 3.1 9.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
• Weakness: CWE-77, CWE-78, CWE-749.
• NVD published 2026-11-05, status Analyzed.

Anyone running SignalWire FreeSwitch in the version ranges below. Internet-facing instances are the priority.

• freeswitch freeswitch: up to (not including) 1.11.3.

Version ranges come from the NVD CPE configuration. Confirm against the vendor advisory before you rely on them.

• Exploited in the wild: added to the CISA Known Exploited Vulnerabilities catalog on 2026-11-09; federal remediation due date 2026-11-12.

CISA added CVE-2026-116779 to its Known Exploited Vulnerabilities catalog on 2026-11-09. A KEV listing means CISA has evidence that attackers are using the flaw against real systems, not just that it could be used.

If your business runs SignalWire FreeSwitch, put this at the top of the patch list. CISA gave US federal agencies until 2026-11-12 to deal with it, and that is a sensible deadline for a small business too.

• Patch. Update to a fixed release: freeswitch freeswitch 1.11.3 or later. These versions come from NVD's configuration data, so confirm them against the advisory from SignalWire.
• If you cannot patch yet. Follow CISA's 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.
• Check your exposure. Find out whether SignalWire FreeSwitch can be reached from the internet, for example a VPN portal, an admin login page or a file-transfer site. Your firewall's port-forwarding rules and your IT provider's list of public-facing systems are the quickest places to look. Exposed copies come first.
• When to call IT support. Call your IT support provider now if you run SignalWire FreeSwitch and cannot confirm it is updated, if it was reachable from the internet before you patched it, or if you notice accounts, sign-ins or files you do not recognise. The last two can mean the system was already hit, and checking that properly takes someone who can read the logs.

• EPSS (probability of exploitation activity in the next 30 days): 1.30%, higher than 71% of all scored CVEs (as of 2026-11-09).
• CVERadar threat level: 64/100 (see methodology).
• Likely ATT&CK techniques: T1190 Exploit Public-Facing Application (inferred); T1059 Command and Scripting Interpreter (inferred).

1. Find every instance. List where SignalWire FreeSwitch runs, including test, DR and forgotten internet-facing systems, and record the installed version.
2. Upgrade to a fixed release. freeswitch freeswitch: 1.11.3 or later. Get the build from the vendor advisory.
3. If you can't patch today, follow CISA's 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.
4. Verify the fix. Re-run the version check on every instance and confirm it reports the fixed build (1.11.3 or later). Re-scan from outside if the service is exposed.
5. Hunt for signs of earlier compromise. If the system was exposed before you patched, assume it may have been hit and check the items below.
6. Rotate credentials stored on or used by the affected system if you cannot rule out compromise, and keep the logs you reviewed.

Detection hints

• T1190 Exploit Public-Facing Application: Review WAF, reverse-proxy and application logs for unusual requests to FreeSwitch (odd paths, oversized or encoded payloads, bursts of errors), going back to at least 2026-11-05.
• T1059 Command and Scripting Interpreter: Watch for the service process spawning shells or script interpreters.

Detection commands are generic starting points, not CVE-specific signatures. Use the indicators from the vendor advisory when it publishes them.

• NVD: CVE-2026-116779 nvd.nist.gov/vuln/detail/CVE-2026-116779
• CVE.org record www.cve.org/CVERecord?id=CVE-2026-116779
• Vendor link from CISA KEV github.com/signalwire/freeswitch/security/advisories/GHSA-mg63-h38w-8p
• Patch github.com/signalwire/freeswitch/commit/7015f6a73ab3d67fed5fbfc277ecfb
• Patch github.com/signalwire/freeswitch/pull/3135
• Release Notes github.com/signalwire/freeswitch/releases/tag/v1.11.3
• CISA KEV catalog www.cisa.gov/known-exploited-vulnerabilities-catalog
• FIRST EPSS (2026-11-09) api.first.org/data/v1/epss?cve=CVE-2026-116779