CVE-2026-49840 (GCVE-0-2026-49840)
Vulnerability from cvelistv5 – Published: 2026-06-09 16:00 – Updated: 2026-06-09 17:00
VLAI
EPSS
VEX
Title
FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing
Summary
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.
Severity
9.1 (Critical)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-09 16:59 UTC
CWE
Assigner
GitHub_M
CNA
References
2 references
| URL | Tags |
|---|---|
| https://github.com/signalwire/freeswitch/security… | x_refsource_CONFIRM |
| https://github.com/signalwire/freeswitch/releases… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| signalwire | freeswitch |
Affected:
< 1.11.1
|
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