Golang 1.26.x < 1.26.9 / 1.27.x < 1.27.2 Multiple Vulnerabilities

critical Nessus Plugin ID 366456

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Synopsis

An application installed on the remote host is affected by multiple vulnerabilities.

Description

The version of Golang running on the remote host is 1.26.x prior to 1.26.9, or 1.27.x prior to 1.27.2. It is, therefore, affected by multiple vulnerabilities in the standard library and the toolchain, as referenced in the golang-announce advisory, including:

- On Windows, when the target of Root.Mkdir or Root.MkdirAll is a junction pointing to an empty location, the operation can create a directory at the junction target even when that target is located outside the root. This only applies to operations where the last path component is a junction (path/to/junction, but not path/junction/target). (CVE-2026-56857)

- The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control. (CVE-2026-78663)

- When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive response, Transport returns the connection to the idle pool. Because CONNECT requests do not have a request body, the server may interpret the trailing body bytes as a subsequent pipelined HTTP/1.1 request on the connection, leaving the pooled connection desynchronized and causing the next caller that reuses it to read the response to the injected request. In reverse proxies (including httputil.ReverseProxy) that forward CONNECT requests through a shared Transport, this can lead to cross-user response poisoning. (CVE-2026-56866)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Golang Go version 1.26.9, 1.27.2 or later.

Plugin Details

Severity: Critical

ID: 366456

File Name: golang_1_26_9_1_27_2.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 10/16/2026

Updated: 10/16/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.49

CVSS v2

Risk Factor: Critical

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2026-56857

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vulnerability Information

CPE: cpe:/a:golang:go

Required KB Items: installed_sw/Golang Go Programming Language

Patch Publication Date: 10/8/2026

Vulnerability Publication Date: 10/8/2026

Reference Information

CVE: CVE-2026-56857, CVE-2026-56866, CVE-2026-78659, CVE-2026-78660, CVE-2026-78663, CVE-2026-78667, CVE-2026-78669, CVE-2026-94439, CVE-2026-94440, CVE-2026-94444, CVE-2026-94447, CVE-2026-94448, CVE-2026-97030, CVE-2026-97031, CVE-2026-97032

IAVB: 2026-B-0296

Detections

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