CVE-2026-116781: freeswitch Memory Corruption — 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, ws_read_frame() unmasked a WebSocket payload by iterating wsh->datalen, which included frame headers, while indexing from the payload pointer. A masked frame filling the 64 KiB receive buffer could therefore XOR up to 14 bytes beyond the buffer, and the exact-capacity case also wrote a terminating NUL one byte out of bounds. The flaw is reachable before authentication when mod_xml_rpc and its opt-in WebSocket endpoint are enabled, while both features are disabled in the stock configuration. The writes remain within the same connection handle's adjacent outbound buffer, so neither a process crash nor cross-session disclosure has been demonstrated. This issue is fixed in version 1.11.2.

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CVSS v3.1 Score

5.3

MEDIUM

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

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.19%

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-193 CWE-193

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
freeswitch	freeswitch	< 1.11.2

References

Advisories & Patches

https://github.com/signalwire/freeswitch/commit/fb9f37b9c7869630ee52a3ae87399fbbf99ad74d https://github.com/signalwire/freeswitch/security/advisories/GHSA-4cg6-rvh2-cw74

Other References

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

Frequently Asked Questions

What is CVE-2026-116781? +

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, ws_read_frame() unmasked a WebSocket payload by iterating wsh->datalen, which included frame headers, while indexing from the payload pointer. A masked frame filling the 64 KiB receive buffer could therefore XOR up to 14 bytes beyond the buffer, and the exact-capacity case also wrote a terminating NUL one byte out of bounds. The flaw is reachable before authentication when mod_xml_rpc and its opt-in WebSocket endpoint are enabled, while both features are disabled in the stock configuration. The writes remain within the same connection handle's adjacent outbound buffer, so neither a process crash nor cross-session disclosure has been demonstrated. This issue is fixed in version 1.11.2. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-116781? +

CVE-2026-116781 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-116781? +

CVE-2026-116781 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-2026-116781? +

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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