Plaintext TLS traffic via stale retry hook
Published Jun 23, 2026 · Updated Jun 23, 2026
Cleartext transmission in the Node.js TLS layer of Deno 2.0.0 through 2.7.7 allows remote attackers to read or alter TLS traffic. On an address-family retry, socket reinitialization copies a TLS upgrade callback bound to the failed handle, so the replacement TCP socket remains plaintext. Exploitation requires autoSelectFamily, an attacker-induced initial family failure, and application writes before secureConnect; autoSelectFamily is enabled by default.
Summary
What happened
Cleartext transmission in the Node.js TLS layer of Deno 2.0.0 through 2.7.7 allows remote attackers to read or alter TLS traffic. On an address-family retry, socket reinitialization copies a TLS upgrade callback bound to the failed handle, so the replacement TCP socket remains plaintext. Exploitation requires autoSelectFamily, an attacker-induced initial family failure, and application writes before secureConnect; autoSelectFamily is enabled by default.
The record
- CVE
- CVE-2026-44726
- Published
- Jun 23, 2026
- Updated
- Jun 23, 2026
- Vendor
- Deno Land Inc.
- Product
- Deno
- Classifications
- CWE-319, CAPEC-117, T1557
- Attack vector
- network
- Privileges
- unauthenticated
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=>= 2.0.0, < 2.7.8
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
- Upstream TLS fallback proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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