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FreeswitchApplication

CVE-2026-45771

HIGH · 7.5 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 1.11.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FreeSWITCH versions before 1.11.0 contain a vulnerable bundled XML parser that expands nested <!ENTITY> declarations without depth or count bounds, enabling a 'billion laughs' exponential expansion attack. The attacker exploits this by sending a crafted PIDF body within a SIP PUBLISH request, which is parsed before any digest authentication check, allowing an unauthenticated remote attacker to cause severe CPU and memory exhaustion with a single request.

MitigationUpgrade FreeSWITCH to version 1.11.0 or later which patches the vulnerable XML parser. If immediate upgrade is not feasible, consider deploying upstream filtering or network-level controls to block suspicious XML payloads in SIP traffic.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FreeswitchApplication
Affected:< 1.11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed FreeSWITCH version
    Run 'freeswitch -version' or 'fs_cli -v' from the FreeSWITCH installation directory, or check the package manager for the installed freeswitch package version
    Affected if The reported version is any release before 1.11.0 (e.g., 1.10.x, 1.8.x, 1.6.x, etc.)
  2. Identify if XML processing modules are loaded
    Check the FreeSWITCH configuration files (autoload_configs/modules.conf.xml) for loaded modules that process XML, such as mod_xml_cdr, mod_xml_rpc, or mod_xml_curl
    Affected if Any XML-processing modules are enabled and the FreeSWITCH version is below 1.11.0
  3. Verify SIP PUBLISH request handling
    Inspect the SIP profile configurations (in sip_profiles/ directory) to determine if PUBLISH method is allowed. Check for 'publish' in the enabled SIP methods or verify via 'sofia status profile <profile>' command
    Affected if SIP PUBLISH requests are accepted and processed by any enabled SIP profile
  4. Review SIP traffic for PUBLISH requests
    Capture SIP traffic on the listening ports (typically UDP/TCP 5060) or review SIP access logs for incoming PUBLISH requests
    Affected if The system is receiving SIP PUBLISH requests from untrusted sources and runs a version below 1.11.0

The environment is affected if FreeSWITCH version is below 1.11.0 and the system accepts or processes SIP PUBLISH requests, regardless of XML module loading status.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.11.0 or later
Fixed in 1.11.0
Interim mitigation

Upgrade FreeSWITCH to version 1.11.0 or later which patches the vulnerable XML parser. If immediate upgrade is not feasible, consider deploying upstream filtering or network-level controls to block suspicious XML payloads in SIP traffic.

Recommended fix High confidence

FreeSWITCH 1.11.0

  1. Download and install FreeSWITCH version 1.11.0 or later from the official FreeSWITCH repository
  2. Ensure all SIP PUBLISH handling is tested after upgrade to verify the XML parser fix is functioning correctly
  3. Monitor system resources (CPU and memory) during SIP PUBLISH processing to confirm the vulnerability is mitigated

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Freeswitch Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45771 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data