FreeSWITCH: Out-of-bounds read in RTCP NACK feedback parsing
Affects FreeSWITCH deployments that terminate video calls with RTCP active on the video stream. Fixed in 1.11.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 1.11.2
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 33/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
FreeSWITCH, a software telecom switching stack, is affected by an out-of-bounds read flaw in its RTCP NACK feedback parsing. A remote attacker on the network, without logging in, can send crafted RTCP packets to an active video call and crash FreeSWITCH, ending every active call.
Read the original 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 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.
cve.now Index
- Exploitation0/40No signal
- Exposure25/25Default setups, CISA rates it automatable
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 73 if added to CISA KEV
- Would score about 68 if CISA's SSVC rates exploitation active
What to do
Check every install: default setups are affected.
Upgrade to a fixed version: 1.11.2.
Workaround: Restricting the media port range at the firewall to known media peers reduces exposure
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- signalwire freeswitch
fixed in 1.11.2
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-116784
Is CVE-2026-116784 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The bug is an out-of-bounds read in the parsing of RTCP NACK feedback. Reading past the RTCP buffer crashes the FreeSWITCH process, which terminates every call the instance is handling.Source: github.com, github.com
Which versions are affected by CVE-2026-116784?
freeswitch: before 1.11.2.Source: cve.now feed data
Am I affected, and how do I check?
Affected are FreeSWITCH deployments that terminate video calls with RTCP active on the video stream. RTCP can be enabled for a call by an a=rtcp-fb or a=rtcp attribute in the remote SDP, even without RTCP interval settings in the SIP profile. Check the installed FreeSWITCH version and whether video calls in the deployment run with RTCP active.Source: github.com, github.com
How do I fix CVE-2026-116784?
Upgrade FreeSWITCH to 1.11.2 or later, which contains the fix that bounds the RTCP NACK feedback loop to the validated length.Source: github.com, github.com