CVE-2026-49840
9.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Exploitability: 3.9 / Impact: 5.2
Source: security-advisories@github.com (Secondary)
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.
Affected (1)
Products: Freeswitch: Freeswitch
Configuration A
| Vulnerable Software | Affected Versions |
|---|---|
| Before 1.11.1 |
Related CWEs
CWE-122
Heap-based Buffer Overflow
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
CWE-195
Signed to Unsigned Conversion Error
The product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive.
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.
CWE-787
Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
References (2)
Source: security-advisories@github.com
Release Notes
Source: security-advisories@github.com
Third Party Advisory
Timeline
No history available yet.