SecuriTricks - CVE-2026-49840

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, esl_recv_event() parses Content-Length with atol() and passes the result straight to malloc(len + 1) with no sign or magnitude check. A malicious or man-in-the-middle ESL peer can send a frame with a negative Content-Length to corrupt the heap of, or crash, any process linked against libesl, before the client has authenticated to that peer. This issue has been patched in version 1.11.1.

Product(s) Impacted

Vendor	Product	Versions
Freeswitch	Freeswitch	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-20

Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	freeswitch	freeswitch	/	/	/	/	/	/	/	/

References

https://github.com/signalwire/freeswitch/releases/tag/v1.11.1

https://github.com/signalwire/freeswitch/security/advisories/GHSA-g597-9fgg-ghg9

CVSS Score

9.1 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: NONE
Integrity Impact: HIGH
Availability Impact: HIGH

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

View Vector String

Timeline

Published: June 9, 2026, 5:17 p.m.
Last Modified: June 10, 2026, 3:06 p.m.

Status : Analyzed

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-49840