# CVE-2026-94439 — Go standard library net/http

> As of 2026-10-09, CVE-2026-94439 is a HIGH-severity vulnerability in Go standard library net/http, CVSS v3.1 7.5, EPSS 0.1% (7.0th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-94439 as of 2026-10-09; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-10-09

## What is 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.

The record classifies CVE-2026-94439 under weakness class [CWE-444](https://intel.threadlinqs.com/cwe/CWE-444). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 2 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 7.0% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-10-08, last modified 2026-10-09

## Is CVE-2026-94439 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Go standard library](https://intel.threadlinqs.com/vendors/go-standard-library): net/http

## How to fix CVE-2026-94439

No vendor patch reference has been recorded for CVE-2026-94439 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-94439

No threat campaign in the Threadlinqs corpus currently references CVE-2026-94439, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, GitHub Security Advisories, FIRST EPSS, NVD. Last verified by Threadlinqs on 2026-10-10. This product uses the NVD API but is not endorsed or certified by the NVD.

**Other references**

- [go.dev](https://go.dev/cl/847311)
- [go.dev (81744)](https://go.dev/issue/81744)
- [groups.google.com](https://groups.google.com/g/golang-announce/c/U2fTuyDJznI)
- [pkg.go.dev](https://pkg.go.dev/vuln/GO-2026-6613)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-94439
Full detection coverage and IOCs for threats exploiting CVE-2026-94439 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp