CVE-2023-51443Public exploitNetwork attack vector

Call teardown via unvalidated DTLS ClientHello

Published Dec 27, 2023 · Updated Nov 4, 2025

Denial of service in FreeSWITCH before 1.10.11 allows remote attackers to terminate DTLS-SRTP calls via crafted DTLS packets. The RTP DTLS handler accepts a ClientHello from outside the ICE-negotiated path, and an invalid cipher-suite error tears down the media session and its SIP signaling. Network access to a dynamically allocated RTP port and winning a race with the legitimate caller are required; repeated packets can interrupt new encrypted calls.

CVSS severity7.5
High
EPSS probability1.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in FreeSWITCH before 1.10.11 allows remote attackers to terminate DTLS-SRTP calls via crafted DTLS packets. The RTP DTLS handler accepts a ClientHello from outside the ICE-negotiated path, and an invalid cipher-suite error tears down the media session and its SIP signaling. Network access to a dynamically allocated RTP port and winning a race with the legitimate caller are required; repeated packets can interrupt new encrypted calls.

The record

CVE
CVE-2023-51443
Published
Dec 27, 2023
Updated
Nov 4, 2025
Vendor
SignalWire
Product
FreeSWITCH
Classifications
CWE-703, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.10.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SignalWire · FreeSWITCHversion=< 1.10.11

Published CVSS scores

5.9NISTCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-703Improper Check or Handling of Exceptional Conditions
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo