Unauthenticated rule bypass via fragmented TLS ClientHello
Published Jan 29, 2026 · Updated Jan 29, 2026
Access control bypass in TrustTunnel before 0.9.115 allows remote attackers to evade client-random rules via a fragmented TLS ClientHello. TlsListener::listen reads only the initially available 1,024 bytes; a partial parse yields no client random, so RulesEngine::evaluate skips client_random_prefix conditions. Exposure requires a client_random_prefix policy with a different fallthrough outcome, allowing a crafted connection to reach a permitted path or block legitimate traffic.
Summary
What happened
Access control bypass in TrustTunnel before 0.9.115 allows remote attackers to evade client-random rules via a fragmented TLS ClientHello. TlsListener::listen reads only the initially available 1,024 bytes; a partial parse yields no client random, so RulesEngine::evaluate skips client_random_prefix conditions. Exposure requires a client_random_prefix policy with a different fallthrough outcome, allowing a crafted connection to reach a permitted path or block legitimate traffic.
The record
- CVE
- CVE-2026-24904
- Published
- Jan 29, 2026
- Updated
- Jan 29, 2026
- Vendor
- TrustTunnel
- Product
- TrustTunnel
- Classifications
- CWE-284, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 29, 2026CVE publishedPublication date reported by the CVE source.
- Jan 29, 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=< 0.9.115
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.
Public exploit references
- Upstream fragmented ClientHello proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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