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Public proof of conceptFix available

CVE-2023-51443

A public proof of concept exists; no exploitation attested.

  • Published2023-12-27
  • Fixed in1.10.11
  • WeaknessCWE-703

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2023-12-2717:15CVE publishedNVD

Versions per branch

NVD
Freeswitch
BranchAffectedFixed in
1.10< 1.10.111.10.11

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • signalwire freeswitch
    Affected
    • = < 1.10.11no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2024-01-08

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • freeswitchCleanStartall versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.24all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.23all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.22all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.21all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.20all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.19all versions · fixed in 1.10.11-r0
  • freeswitchAlpine:v3.18all versions · fixed in 1.10.11-r0

1 more package range on OSV.dev

Full record on NVD

Fix

  1. Update Freeswitch to 1.10.11

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2024-08-27
  • CNACVSS 3.17.5known since 2026-10-23
  • NVDCVSS 3.15.9read 2026-10-23
  • CNAweakness (CWE)CWE-703known since 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-08
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2023-12-27
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2023-51443?

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.

Is CVE-2023-51443 actively exploited?

A proof-of-concept exploit exists for CVE-2023-51443, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-51443?

CVE-2023-51443 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

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