FreeSWITCH: Pre-authentication heap buffer overflow in core XML empty-entity decoding
Affects FreeSWITCH before 1.11.2 on SIP profiles with manage-presence enabled, such as the default internal profile, when an XML DTD declares an entity with an empty value. 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? →
- 30/100 · 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
Summary
FreeSWITCH, an open-source telecommunications platform, is affected by a heap buffer overflow in its core XML decoding that can be triggered remotely, without logging in, through a crafted SIP PUBLISH request. An attacker who reaches a SIP profile with presence management and DTD processing enabled can corrupt heap memory and crash the FreeSWITCH process, interrupting all active calls.
Read the original description
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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure22/25Default setups, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.2/10CVSS 8.2
- No patch0/5No signal
What would change the score
- Would score about 70 if added to CISA KEV
- Would score about 65 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: Set the xml_disable_dtd core variable, or set manage-presence=false on exposed profiles, or restrict the SIP listener to trusted networks until upgraded.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- signalwire freeswitch
fixed in 1.11.2
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-116788
Is CVE-2026-116788 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?
When a DTD declares an entity with an empty replacement value, the core XML decoder can write past the end of a heap buffer before any authentication happens. The validated impact is denial of service, since heap memory is corrupted and the FreeSWITCH process is lost. Remote code execution has not been demonstrated.Source: github.com
Which versions are affected by CVE-2026-116788?
freeswitch: before 1.11.2.Source: cve.now feed data
Am I affected, and how do I check?
FreeSWITCH versions before 1.11.2 are in scope, but only where a SIP profile has manage-presence enabled. The vanilla internal profile has it enabled by default, and the external profile does not. Check the manage-presence setting in each SIP profile's configuration and confirm the running version with the FreeSWITCH version command.Source: github.com
How do I fix CVE-2026-116788?
Upgrade to FreeSWITCH 1.11.2 or later, which skips the buffer resize when the replacement is empty.Source: github.com