FreeSWITCH: Pre-authentication stack buffer overflow in mod_xml_rpc HTTP directory authentication
Affects FreeSWITCH builds before 1.11.2 that load mod_xml_rpc with its HTTP listener exposed and a directory entry of 58+ characters. 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
- Specific setups only
Do first: Check whether your setup matches what the bug needs. mod_xml_rpc is loaded and its HTTP listener is exposed A directory entry's user@domain:password string is 58 characters or longer Affected code builds the credential in a 256-byte buffer but encodes it into an 80-byte buffer
- 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? →
- 20/100 · 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? →
- Specific setups only
- 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, a software telecom switching stack, is affected by a stack buffer overflow in its mod_xml_rpc HTTP directory authentication that can be reached remotely, without logging in, on an exposed listener where the module is loaded and the configured credential is long enough to overflow the buffer. An attacker can crash FreeSWITCH, which ends all active calls, though remote code execution has not been demonstrated.
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, http_directory_auth() rebuilt an expected user@domain:password credential and base64-encoded it into an 80-byte buffer using an encoder without an output-length argument. A configured credential longer than 57 characters overflowed the stack before the supplied HTTP Basic password was compared. An unauthenticated client only needed to name an existing directory user on an exposed mod_xml_rpc HTTP listener; the module is built but not loaded by the stock configuration. The overflow can corrupt the stack and crash FreeSWITCH, ending every active call, although the overrun bytes come from the configured credential and remote code execution has not been demonstrated. This issue is fixed in version 1.11.2.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- 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 70 if added to CISA KEV
- Would score about 65 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
mod_xml_rpc is loaded and its HTTP listener is exposed A directory entry's user@domain:password string is 58 characters or longer Affected code builds the credential in a 256-byte buffer but encodes it into an 80-byte bufferUpgrade to a fixed version: 1.11.2.
Workaround: Leave mod_xml_rpc unloaded, or restrict its listener to trusted hosts at the network layer.
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-2026-116570
Is CVE-2026-116570 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?
A long user@domain:password directory credential overflows a fixed-size stack buffer in mod_xml_rpc's HTTP directory authentication, before any login. The result is stack corruption that crashes the FreeSWITCH process. Remote code execution has not been demonstrated.Source: github.com, github.com
Which versions are affected by CVE-2026-116570?
freeswitch: before 1.11.2.Source: cve.now feed data
Am I affected, and how do I check?
Versions before 1.11.2 are affected, but only where mod_xml_rpc is loaded, its HTTP listener is exposed (default port 8080), and a directory entry's user@domain:password string is 58 characters or longer. To check, look at whether mod_xml_rpc is listed among loaded modules and whether the listener is reachable, and check the length of directory credentials.Source: github.com, github.com
How do I fix CVE-2026-116570?
Upgrade to FreeSWITCH 1.11.2, which the advisory says all users should do as soon as possible. If upgrading is not immediately possible, leave mod_xml_rpc unloaded or restrict its listener to trusted hosts at the network layer.Source: github.com, github.com