Pre-authentication process termination in FreeSWITCH Event Socket
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-190 and the CVSS impact.
Summary
SignalWire FreeSWITCH before 1.11.2 is affected. Its mod_event_socket module uses an unauthenticated Content-Length value directly as an allocation size, so negative or very large values overflow a calculation and terminate the process (CWE-190). Any host admitted by apply-inbound-acl can crash FreeSWITCH with its first packet, since the header is parsed before the Event Socket password check. Process termination drops all active calls until the service restarts.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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, mod_event_socket used an unauthenticated Content-Length value directly as the allocation size for an Event Socket message body. Negative or extremely large values could overflow the terminator calculation or force an allocation failure through a helper that aborts the FreeSWITCH process. The header is parsed before the Event Socket password, so any host admitted by apply-inbound-acl can trigger termination with its first packet; the default loopback ACL limits ordinary installations to local clients. The outbound socket dialplan path is also affected when FreeSWITCH connects to a hostile application server, and process termination drops every active call until the service is restarted. This issue is fixed in version 1.11.2.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| signalwire | freeswitch | before 1.11.2 | 1.11.2 | Patch available | CNA |
- freeswitch Vendorsignalwire Affected before 1.11.2 Fixed in 1.11.2 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:* | — | — | freeswitch |
- cpe:2.3:a:freeswitch:freeswitch:*:*:*:*:*:*:*:* Versions — — ·freeswitch
Remediation
Upgrade SignalWire FreeSWITCH to version 1.11.2, the fixed version.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA freeswitch (signalwire) Fixed in 1.11.2
Vendor assessments
Timeline
- 2026-11-05 Threatist record created from CVE-2026-116787
- 2026-11-05 CISA SSVC decision points changed
- 2026-11-05 Priority changed: MEDIUM → LOW
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
More signalwire vulnerabilities
- TI-2023-08915 heap-over-flow in stun_parse_attribute in sofia-sip CVSS 3.1CRITICAL 9.8
- TI-2022-13049 Heap-based Buffer Overflow and Out-of-bounds Write in Sofia-SIP CVSS 3.1CRITICAL 9.8
- TI-2023-28097 FreeSWITCH susceptible to Denial of Service via DTLS Hello packets during call initiation CVSS 3.1HIGH 7.5
- TI-2023-20909 Resource allocation without limits in signalwire freeswitch CVSS 3.1HIGH 7.5
- TI-2023-20908 FreeSWITCH allows remote users to trigger out of bounds write by offering an ICE candidate with unknown component ID CVSS 3.1HIGH 7.5
- TI-2023-15601 heap-over-flow and integer-overflow in sofia-sip CVSS 3.1HIGH 7.5
Sources
- CVE-2026-116787 · CVE Program
- CVE-2026-116787 · NVD
- FIRST EPSS
- CVE-2026-116787 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences