CVE-2021-41145: FreeSWITCH susceptible to Denial of Service via SIP flooding

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-10-25 · updated 2026-06-17
Weakness: CWE-400

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. FreeSWITCH prior to version 1.10.7 is susceptible to Denial of Service via SIP flooding. When flooding FreeSWITCH with SIP messages, it was observed that after a number of seconds the process was killed by the operating system due to memory exhaustion. By abusing this vulnerability, an attacker is able to crash any FreeSWITCH instance by flooding it with SIP messages, leading to Denial of Service. The attack does not require authentication and can be carried out over UDP, TCP or TLS. This issue was patched in version 1.10.7.

Affected products

signalwire freeswitch: before 1.10.7 — fixed in 1.10.7

How to fix

Upgrade to a fixed version: signalwire freeswitch 1.10.7. Check the vendor advisory for mitigations.

References

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