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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-49840 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/signalwire/freeswitch/releases/tag/v1.11.1 GitHub, Inc. Release Notes 
https://github.com/signalwire/freeswitch/security/advisories/GHSA-g597-9fgg-ghg9 GitHub, Inc. Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-20 Improper Input Validation GitHub, Inc.  
CWE-122 Heap-based Buffer Overflow GitHub, Inc.  
CWE-195 Signed to Unsigned Conversion Error GitHub, Inc.  
CWE-787 Out-of-bounds Write GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-49840
NVD Published Date:
06/09/2026
NVD Last Modified:
06/10/2026
Source:
GitHub, Inc.