{"cve":"CVE-2023-51443","nvd":{"published":"2023-12-27T17:15:08.093","modified":"2026-06-17T06:40:58.167","status":"Modified","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. Prior to version 1.10.11, when handling DTLS-SRTP for media setup, FreeSWITCH is susceptible to Denial of Service due to a race condition in the hello handshake phase of the DTLS protocol. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. If an attacker manages to send a ClientHello DTLS message with an invalid CipherSuite (such as `TLS_NULL_WITH_NULL_NULL`) to the port on the FreeSWITCH server that is expecting packets from the caller, a DTLS error is generated. This results in the media session being torn down, which is followed by teardown at signaling (SIP) level too. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable FreeSWITCH servers for calls that rely on DTLS-SRTP. To address this vulnerability, upgrade FreeSWITCH to 1.10.11 which includes the security fix. The solution implemented is to drop all packets from addresses that have not been validated by an ICE check.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9},"cwes":["CWE-703"],"references":["http://packetstormsecurity.com/files/176393/FreeSWITCH-Denial-Of-Service.html","https://github.com/signalwire/freeswitch/commit/86cbda90b84ba186e508fbc7bfae469270a97d11","https://github.com/signalwire/freeswitch/security/advisories/GHSA-39gv-hq72-j6m6","http://packetstormsecurity.com/files/176311/FreeSWITCH-1.10.10-Denial-Of-Service.html","http://packetstormsecurity.com/files/176393/FreeSWITCH-Denial-Of-Service.html"],"products":["freeswitch:freeswitch"],"source":"nvd","synced_at":"2026-10-19T21:43:38.875533635+00:00"},"epss":{"cve":"CVE-2023-51443","score":0.01485,"percentile":0.74025,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}