CVE-2026-94439HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
Updated under an hour ago ()
Does this affect you?
It affects Go standard library net/http. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.32%, higher than 23% of scored CVEs.
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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.
- CVSS
- 7.5 HIGH (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.32% (percentile 23)
- Assigned by
- Go
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 9, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Go standard library net/http go_standard_library:net_http (from the name) | before 1.26.9; from 1.27.0-0 before 1.27.2 | CNA record |
References
- https://go.dev/cl/847311
- https://go.dev/issue/81744
- https://groups.google.com/g/golang-announce/c/U2fTuyDJznI
- https://pkg.go.dev/vuln/GO-2026-6613
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.