CVE-2026-116571: freeswitch Stack Overflow — Fix

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.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0037

Probability of exploitation

0.32%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

Affected Products

Vendor	Product	Versions
freeswitch	freeswitch	< 1.11.2

References

Advisories & Patches

https://github.com/signalwire/freeswitch/commit/2ab0a534fdc25301daf95590e90a756a76bf0950 https://github.com/signalwire/freeswitch/security/advisories/GHSA-qmh2-f6cv-79mf

Other References

https://github.com/signalwire/freeswitch/releases/tag/v1.11.2

Frequently Asked Questions

What is CVE-2026-116571? +

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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-116571? +

CVE-2026-116571 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0037, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-116571? +

CVE-2026-116571 affects products from freeswitch, specifically: freeswitch. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-116571? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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