Heap Overflow in FreeSWITCH Software Due to Buffer Limitations
CVE-2026-49841

9.8CRITICAL

Key Information:

Vendor

Signalwire

Status
Freeswitch
Vendor
CVE Published:
9 June 2026

What is CVE-2026-49841?

The mod_verto HTTP request handler in FreeSWITCH versions prior to 1.11.1 is susceptible to a heap overflow vulnerability. This problem arises from the allocation of a fixed 2 MiB buffer for handling POST requests with a content type of application/x-www-form-urlencoded. However, the module allows a Content-Length of up to nearly 10 MiB, leading to potential heap overflow of around 8 MiB, which can be exploited by attackers before the HTTP basic-auth check is performed. This vulnerability has been addressed in version 1.11.1, thus it is recommended to upgrade to mitigate possible risks.

Affected Version(s)

freeswitch < 1.11.1

References

https://github.com/signalwire/freeswitch/security/advisor...
x_refsource_CONFIRM
https://github.com/signalwire/freeswitch/releases/tag/v1....
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CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.