CVE-2026-49841 FreeSWITCH: Pre-authentication heap buffer overflow in `mod_verto` HTTP POST body read
An attacker can trigger a pre-authentication heap buffer overflow in FreeSWITCH's mod_verto module, potentially leading to remote code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49841?
CVE-2026-49841 is a critical memory corruption vulnerability in signalwire freeswitch, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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 version 1.11.1, the mod_verto 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.
Which versions are affected by CVE-2026-49841?
It affects 1 product.
Products include Freeswitch Freeswitch.
How do I fix CVE-2026-49841?
No fix has been published for CVE-2026-49841 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-49841 being exploited?
There is no known exploitation of CVE-2026-49841 in the wild and no public exploit code.
Other vulnerabilities in signalwire freeswitch
- CVE-2019-19492 Hardcoded credentials in n/a
- CVE-2026-49840 FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing
- CVE-2021-41145 FreeSWITCH susceptible to Denial of Service via SIP flooding
- CVE-2026-45771 Freeswitch Denial-of-Service in SIP PUBLISH Requests via XML Entity Expansion
- CVE-2026-49475 FreeSWITCH: Out-of-bounds memory access in core STUN attribute parsing
Sources
Also known as GHSA-wfrq-qvg2-f88f.