Vulnerability Intelligence Report
HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
CVE-2026-94439
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.
No Active Exploit Signals
CVSS Base Score
7.5
HIGH
Exploitability:3.9
Impact Score:3.6
EPSS Probability:0.18%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
—
Weaknesses (CWE)
CWE-444 ↗CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Go standard library | net/http | 0 < 1.26.9 (affected), 1.27.0-0 < 1.27.2 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
0.181%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Go Project · Vendor · USA |
| Reserved | 2026-09-21T16:43:04 |
| Published | 2026-10-08T22:53:59 |
| Last Updated | 2026-10-09T16:52:15 |
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