CVE-2026-45771 Freeswitch Denial-of-Service in SIP PUBLISH Requests via XML Entity Expansion
Unauthenticated attackers can cause denial of service in FreeSWITCH via XML entity expansion in SIP PUBLISH requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-45771?
CVE-2026-45771 is a high-severity denial of service vulnerability in signalwire freeswitch, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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 1.11.0, FreeSWITCH's bundled XML parser expands nested <!ENTITY> declarations without a depth or count bound, so a small DTD can describe a body that expands exponentially ("billion laughs"). The PIDF body of a SIP PUBLISH is fed to this parser before any digest check, letting an unauthenticated network attacker force unbounded CPU and memory consumption with a single request. This issue has been patched in version 1.11.0.
Weakness: CWE-776
Which versions are affected by CVE-2026-45771?
It affects 1 product.
Products include Freeswitch Freeswitch.
How do I fix CVE-2026-45771?
No fix has been published for CVE-2026-45771 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-45771 being exploited?
There is no known exploitation of CVE-2026-45771 in the wild and no public exploit code.
Other vulnerabilities in signalwire freeswitch
- CVE-2026-49841 FreeSWITCH: Pre-authentication heap buffer overflow in `mod_verto` HTTP POST body read
- CVE-2019-19492 Hardcoded credentials in n/a
- CVE-2026-49840 FreeSWITCH: Pre-authentication heap buffer overflow in libesl `Content-Length` parsing
- CVE-2021-41145 FreeSWITCH susceptible to Denial of Service via SIP flooding
- CVE-2026-49475 FreeSWITCH: Out-of-bounds memory access in core STUN attribute parsing
Sources
Also known as GHSA-5vjg-pv56-vg4c.