CVE-2026-49841: FreeSWITCH: Pre-authentication heap buffer overflow in `mod_verto` HTTP POST body read
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 version 1.11.1, the modverto HTTP request handler allocates a fixed 2 MiB buffer for a POST application/x-www-form-urlencoded body but accepts Content-Length up to just under 10 MiB. The body-read loop is bounded by Content-Length rather than the buffer size, producing an attacker-controlled heap overflow of up to ~8 MiB -- before the HTTP basic-auth check runs. This issue has been patched in version 1.11.1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
FreeSWITCH (mod_verto)to a version that resolves this vulnerability.Fixed in 1.11.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-49841?
CVE-2026-49841 has a severity score of 9.8, indicating it is critical.
How do I fix CVE-2026-49841?
To fix CVE-2026-49841, upgrade to FreeSWITCH version 1.11.1 or later.
What type of vulnerability is CVE-2026-49841?
CVE-2026-49841 is a pre-authentication heap buffer overflow vulnerability.
What component is affected by CVE-2026-49841?
CVE-2026-49841 affects the mod_verto HTTP request handler in FreeSWITCH.
What impact does CVE-2026-49841 have on FreeSWITCH?
CVE-2026-49841 can lead to potential remote code execution and service disruption.