Pre-authentication session eviction via attacker-chosen sessid
Published Jun 9, 2026 · Updated Jun 9, 2026
Improper authentication in SignalWire FreeSWITCH before 1.11.1 allows remote attackers to interrupt a known Verto session. The mod_verto JSON-RPC handler binds the first frame's client-supplied sessid into the global session hash before authentication and replaces any existing entry with the same key. Exploitation requires the target session UUID; the legitimate client receives verto.punt, its calls detach, and its WebSocket closes, while authenticated methods remain unavailable to the attacker.
Summary
What happened
Improper authentication in SignalWire FreeSWITCH before 1.11.1 allows remote attackers to interrupt a known Verto session. The mod_verto JSON-RPC handler binds the first frame's client-supplied sessid into the global session hash before authentication and replaces any existing entry with the same key. Exploitation requires the target session UUID; the legitimate client receives verto.punt, its calls detach, and its WebSocket closes, while authenticated methods remain unavailable to the attacker.
The record
- CVE
- CVE-2026-49843
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- SignalWire
- Product
- FreeSWITCH
- Classifications
- CWE-287, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 1.11.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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