FreeSWITCH: Stack buffer overflow in mod_rtmp AVC sequence-header construction
- Exploited
- No known exploitation
- Fix
- Fixed in 1.11.2
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 1.11.2.
- 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? →
- 23/100 · provisional
- 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 deployments that build and load the mod_rtmp module and bridge RTP media into an RTMP leg are affected by a stack buffer overflow in AVC sequence-header construction. An attacker can remotely, without logging in, send oversized SPS and PPS parameter sets during an established H.264 call to crash FreeSWITCH and terminate all active calls, and on builds without stack protection they may gain a limited stack-write primitive, though code execution has not been demonstrated.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
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, rtmp_rtp2rtmpH264() built an AVC decoder configuration record in a fixed stack buffer by copying wire-derived SPS and PPS values without checking that their sizes and framing fit. An established H.264 call bridged toward an RTMP endpoint could supply oversized SPS and PPS parameter sets and overrun the function's stack frame. The flaw affects only deployments that build and load mod_rtmp and bridge RTP media into an RTMP leg; the module is disabled in the stock build and configuration. The corruption can abort FreeSWITCH and terminate every active call, and builds without stack protection receive a limited stack-write primitive, although 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
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity5.9/10CVSS 5.9
- No patch0/5No signal
What would change the score
- Would score about 68 if added to CISA KEV
- Would score about 63 if CISA's SSVC rates exploitation active
- Would score about 28 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 1.11.2.
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.
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Questions about CVE-2026-116571
Is CVE-2026-116571 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
Which versions are affected by CVE-2026-116571?
freeswitch: before 1.11.2.Source: cve.now feed data
How do I fix CVE-2026-116571?
Upgrade to a fixed version: 1.11.2.Source: cve.now feed data