Vulnerability record · CVE-2021-41105 · published 25 October 2021
CVE-2021-41105: Freeswitch improper input validation vulnerability
Freeswitch · Freeswitch
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. When handling SRTP calls, FreeSWITCH prior to version 1.10.7 is susceptible to a DoS where calls can be terminated by remote attackers. This attack can be done continuously, thus denying encrypted calls during the attack. When a media port that is handling SRTP traffic is flooded with a specially crafted SRTP packet, the call is terminated leading to denial of service. This issue was reproduced when using the SDES key exchange mechanism in a SIP environment as well as when using the DTLS key exchange mechanism in a WebRTC environment. The call disconnection occurs due to line 6331 in the source file `switch_rtp.c`, which disconnects the call when the total number of SRTP errors reach a hard-coded threshold (100). By abusing this vulnerability, an attacker is able to disconnect any ongoing calls that are using SRTP. The attack does not require authentication or any special foothold in the caller's or the callee's network. This issue is patched in version 1.10.7.
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. When handling SRTP calls, FreeSWITCH prior to version 1.10.7 is susceptible to a DoS where calls can be terminated by remote attackers. This attack can be done continuously, thus denying encrypted calls during the attack. When a media port that is handling SRTP traffic is flooded with a specially crafted SRTP packet, the call is terminated leading to denial of service. This issue was reproduced when using the SDES key exchange mechanism in a SIP environment as well as when using the DTLS key exchange mechanism in a WebRTC environment. The call disconnection occurs due to line 6331 in the source file `switch_rtp.c`, which disconnects the call when the total number of SRTP errors reach a hard-coded threshold (100). By abusing this vulnerability, an attacker is able to disconnect any ongoing calls that are using SRTP. The attack does not require authentication or any special foothold in the caller's or the callee's network. This issue is patched in version 1.10.7.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| http://seclists.org/fulldisclosure/2021/Oct/43 | ExploitMailing ListThird Party Advisory |
| https://github.com/signalwire/freeswitch/releases/tag/v1.10.7 | Release NotesThird Party Advisory |
| https://github.com/signalwire/freeswitch/security/advisories/GHSA-jh42-prph-gp36 | ExploitThird Party Advisory |
| http://seclists.org/fulldisclosure/2021/Oct/43 | ExploitMailing ListThird Party Advisory |
| https://github.com/signalwire/freeswitch/releases/tag/v1.10.7 | Release NotesThird Party Advisory |
| https://github.com/signalwire/freeswitch/security/advisories/GHSA-jh42-prph-gp36 | ExploitThird Party Advisory |
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2021-41105), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.
