Amazon Linux 2 : golang, --advisory ALAS2-2026-3893 (ALAS-2026-3893)

high Nessus Plugin ID 341867

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of golang installed on the remote host is prior to 1.26.7-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3893 advisory.

Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures. (CVE-2026-33818)

When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this. (CVE-2026-56853)

Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS. (CVE-2026-56858)

Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion. (CVE-2026-56859)

Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.
(CVE-2026-56860)

Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely. (CVE-2026-56862)

A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy (CVE-2026-56864)

A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents.
In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy (CVE-2026-56865)

Tenable has extracted the preceding description block directly from the tested product security advisory.

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

Solution

Run 'yum update golang' or or 'yum update --advisory ALAS2-2026-3893' to update your system.

Plugin Details

Severity: High

ID: 341867

File Name: al2_ALAS-2026-3893.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 8/31/2026

Updated: 8/31/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.17

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

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

CVSS Score Source: CVE-2026-56858

CVSS v3

Risk Factor: High

Base Score: 8.4

Temporal Score: 7.3

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS Score Source: CVE-2026-56865

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:golang-bin, p-cpe:/a:amazon:linux:golang-docs, p-cpe:/a:amazon:linux:golang-misc, p-cpe:/a:amazon:linux:golang-shared, p-cpe:/a:amazon:linux:golang-src, p-cpe:/a:amazon:linux:golang-tests, p-cpe:/a:amazon:linux:golang

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 8/31/2026

Vulnerability Publication Date: 8/13/2026

Reference Information

CVE: CVE-2026-33818, CVE-2026-56853, CVE-2026-56858, CVE-2026-56859, CVE-2026-56860, CVE-2026-56862, CVE-2026-56864, CVE-2026-56865

IAVB: 2026-B-0234

Detections

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