Network sandbox bypass via unchecked resolved WebSocket IPs
Published Jun 23, 2026 · Updated Jun 23, 2026
SSRF in Deno before 2.8.1 allows local users to reach network destinations blocked by --deny-net through a WebSocket connection. The WebSocket path validates the supplied hostname against deny rules before DNS resolution but never applies those rules to the resolved IP addresses. Exploitation requires untrusted or third-party code to run with network access while a --deny-net restriction protects localhost or another internal service.
Summary
What happened
SSRF in Deno before 2.8.1 allows local users to reach network destinations blocked by --deny-net through a WebSocket connection. The WebSocket path validates the supplied hostname against deny rules before DNS resolution but never applies those rules to the resolved IP addresses. Exploitation requires untrusted or third-party code to run with network access while a --deny-net restriction protects localhost or another internal service.
The record
- CVE
- CVE-2026-49860
- Published
- Jun 23, 2026
- Updated
- Jun 23, 2026
- Vendor
- Deno Land
- Product
- Deno
- Classifications
- CWE-918
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 23, 2026CVE publishedPublication date reported by the CVE source.
- Jun 23, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.8.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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