Freeswitch: >> Freeswitch >> 1.5.2 Security Vulnerabilities
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.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-11-05
FreeSWITCH is an open-source software telecommunications platform. Before version 1.11.2, an integer underflow in switch_xml_decode() can cause an undersized heap allocation when an XML document declares an entity with an empty replacement value. Subsequent copying overruns the allocated buffer. An unauthenticated attacker who can reach a SIP profile with presence management enabled and DTD processing permitted can trigger the vulnerability through a crafted SIP PUBLISH request. Exploitation can corrupt heap memory and terminate the FreeSWITCH process, interrupting all active calls. This vulnerability is fixed in version 1.11.2.
CVSS Score
8.2
EPSS Score
0.004
Published
2026-11-05
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, dtls_state_setup() compared a peer certificate with the SDP a=fingerprint only when FreeSWITCH was the DTLS client, not when it held the DTLS server role. An unauthenticated peer able to reach the negotiated media port could complete the DTLS-SRTP handshake with an unrelated certificate, obtain the leg's SRTP keys, decrypt and inject media, and displace the legitimate endpoint; on ICE-enabled legs the peer also needs the connectivity-check credentials from SDP, which generally requires signaling visibility or a position on its path. WebRTC and SIP DTLS-SRTP legs are affected whenever the peer selects the active role, while FreeSWITCH client-role handshakes already perform fingerprint validation. Version 1.11.2 introduces the remediation, which requires rtp_dtls_client_cert_verify_mode=fingerprint.
CVSS Score
7.4
EPSS Score
0.002
Published
2026-11-05
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, FreeSWITCH's inbound ICE handling accepted every connectivity check without cryptographically validating its STUN MESSAGE-INTEGRITY attribute. A network peer able to reach an ICE-enabled leg's media port could forge an ICE connectivity check without SDP credentials, nominate its own address, redirect RTP and DTLS traffic, and terminate the legitimate media path. On unencrypted legs this enables eavesdropping and media injection, while all WebRTC and SIP legs that negotiate ICE are in scope. Version 1.11.2 introduces the remediation, which requires ice_verify_message_integrity=true.
CVSS Score
9.1
EPSS Score
0.003
Published
2026-11-05
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, ws_read_frame() unmasked a WebSocket payload by iterating wsh->datalen, which included frame headers, while indexing from the payload pointer. A masked frame filling the 64 KiB receive buffer could therefore XOR up to 14 bytes beyond the buffer, and the exact-capacity case also wrote a terminating NUL one byte out of bounds. The flaw is reachable before authentication when mod_xml_rpc and its opt-in WebSocket endpoint are enabled, while both features are disabled in the stock configuration. The writes remain within the same connection handle's adjacent outbound buffer, so neither a process crash nor cross-session disclosure has been demonstrated. This issue is fixed in version 1.11.2.
CVSS Score
5.3
EPSS Score
0.003
Published
2026-11-05
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, rtmp_i_connect() passed the first RTMP connect argument to amf0_object_get() without checking whether the AMF value was an object. A string or number in place of an AMF object caused union bytes from the message to be interpreted as node pointers and dereferenced. Any client with network access to an enabled mod_rtmp listener could send the malformed connect command before login; the module is disabled in the stock build and configuration. The invalid read reliably crashes FreeSWITCH and ends every active call, while no write, memory disclosure, or code execution has been demonstrated. This issue is fixed in version 1.11.2.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-11-05
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, udptl_rx_packet() used a peer-controlled FEC entry count directly to fill five-entry FEC arrays in a mod_spandsp T.38 session. A larger count wrote sender-controlled error-recovery data beyond those arrays and persisted the oversized count for a later reconstruction pass. Any peer able to deliver UDPTL to an established T.38 fax session can reach the parser, including deployments using fax applications or a T.38 gateway. The memory corruption can crash FreeSWITCH and end every active call, although remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.
CVSS Score
8.2
EPSS Score
0.006
Published
2026-11-05
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, process_rtcp_report() used an RTPFB NACK packet's declared RTCP header length as its feedback-entry loop bound instead of the datagram length already validated by the caller. A short packet with an oversized declaration could drive reads far beyond the fixed 16 KiB receive buffer. Any peer able to send RTCP to an active video call can reach the flaw, including calls where remote SDP enables video RTCP even though the SIP profile has no explicit RTCP interval configured. The out-of-bounds read can crash FreeSWITCH and terminate every active call, but supplies no write primitive and does not echo the read values to the sender. This issue is fixed in version 1.11.2.
CVSS Score
7.5
EPSS Score
0.004
Published
2026-11-05
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, ws_read_frame() decoded a WebSocket frame's 64-bit extended payload length with a 32-bit byte swap and narrowed the result into a signed length. A value whose surviving low word became negative bypassed the signed size check and was reinterpreted as an enormous unsigned count, causing client bytes to overwrite memory beyond the 64 KiB receive buffer. Any client completing a /socket WebSocket upgrade on an enabled mod_xml_rpc endpoint reached the parser before HTTP authentication; both the module and WebSocket endpoint are disabled by default. The heap overwrite can corrupt connection pointers and crash FreeSWITCH, ending every concurrent session, although remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.
CVSS Score
9.1
EPSS Score
0.011
Published
2026-11-05
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, sofia_handle_sip_i_refer() placed raw Refer-To URI parameters and headers inside a sip_invite_params channel-variable block passed to switch_ivr_originate(). The originate parser treated a comma in the attacker-controlled value as a variable separator, allowing an authenticated caller on a bridged call to inject arbitrary variables into a newly originated leg. An injected execute_on_originate value could invoke the system dialplan application before answer and execute operating-system commands with the FreeSWITCH process privileges. SIP REFER is enabled by default, and the sender needs only a registered account and a call that takes the off-box transfer path, not administrative or Event Socket access. This issue is fixed in version 1.11.2.
CVSS Score
8.8
EPSS Score
0.005
Published
2026-11-05
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