CVE-2021-41105
FreeSWITCH susceptible to Denial of Service via invalid SRTP packets
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
FreeSWITCH susceptible to Denial of Service via invalid SRTP packets
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.
- Record
CVE-2021-41105- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2021-28242
7.5
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.
- Record
EUVD-2021-28242- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
NVD
7.5
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.
- Record
CVE-2021-41105- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
OSVALPINE-CVE-2021-41105
7.5
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.
- Record
ALPINE-CVE-2021-41105- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSV
7.5
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.
- Record
CVE-2021-41105- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
freeswitchAlpine:v3.15 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.16 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.17 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.18 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.19 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.20 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.21 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.22 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.23 |
before 1.10.7-r0 | 1.10.7-r0 |
freeswitchAlpine:v3.24 |
before 1.10.7-r0 | 1.10.7-r0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41105 is a high vulnerability (CVSS 7.5) in Freeswitch, published October 25, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.52%, the 84th percentile. Fixed in freeswitch 1.10.7-r0.