Amazon Linux 2 : amazon-cloudwatch-agent, --advisory ALAS2-2026-3323 (ALAS-2026-3323)

critical Nessus Plugin ID 319860

Synopsis

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

Description

The version of amazon-cloudwatch-agent installed on the remote host is prior to 1.300066.2-2. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3323 advisory.

Arithmetic over induction variables in loops were not correctly checked for underflow or overflow in the Go compiler (cmd/compile). As a result, the compiler would allow for invalid indexing to occur at runtime, potentially leading to memory corruption in programs compiled with affected Go versions. (CVE-2026-27143)

The Go compiler (cmd/compile) incorrectly handled no-op interface conversions, preventing correct determination about non-overlapping memory moves, potentially leading to memory corruption at runtime in programs compiled with affected Go versions. (CVE-2026-27144)

During chain building, the amount of work that is done is not correctly limited when a large number of intermediate certificates are passed in VerifyOptions.Intermediates, which can lead to a denial of service. This affects both direct users of crypto/x509 and users of crypto/tls. (CVE-2026-32280)

Validating certificate chains which use policies is unexpectedly inefficient when certificates in the chain contain a very large number of policy mappings, possibly causing denial of service. This only affects validation of otherwise trusted certificate chains, issued by a root CA in the VerifyOptions.Roots CertPool, or in the system certificate pool. (CVE-2026-32281)

On Linux, if the target of Root.Chmod is replaced with a symlink while the chmod operation is in progress, Chmod can operate on the target of the symlink, even when the target lies outside the root.
(CVE-2026-32282)

If one side of the TLS connection sends multiple key update messages post-handshake in a single record, the connection can deadlock, causing uncontrolled consumption of resources. This can lead to a denial of service. This only affects TLS 1.3. (CVE-2026-32283)

Boolean XPath expressions that evaluate to true can cause an infinite loop in logicalQuery.Select, leading to 100% CPU usage. This can be triggered by top-level selectors such as 1=1 or true().
(CVE-2026-32287)

tar.Reader can allocate an unbounded amount of memory when reading a maliciously-crafted archive containing a large number of sparse regions encoded in the old GNU sparse map format. (CVE-2026-32288)

Context was not properly tracked across template branches for JS template literals, leading to possibly incorrect escaping of content. This could cause actions within JS template literals to be incorrectly escaped, leading to XSS vulnerabilities. (CVE-2026-32289)

When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash. (CVE-2026-33811)

When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0. (CVE-2026-33814)

Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations. (CVE-2026-39820)

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to similarly escape it, leading to XSS. (CVE-2026-39823)

ReverseProxy can forward queries containing parameters not visible to Rewrite functions. When used with a Rewrite function, or a Director function which parses query parameters, ReverseProxy sanitizes the forwarded request to remove query parameters which are not parsed by url.ParseQuery. ReverseProxy does not take ParseQuery's limit on the total number of query parameters (controlled by GODEBUG=urlmaxqueryparams=N) into account. This can permit ReverseProxy to forward a request containing a query parameter that is not visible to the Rewrite function. For example, the query a1=x&a2=x&...&a10000=x&hidden=y can forward the parameter hidden=y while hiding it from the proxy's Rewrite function. (CVE-2026-39825)

If a trusted template author were to write a <script> tag containing an empty 'type' attribute or a 'type' attribute with an ASCII whitespace, the execution of the template would incorrectly escape any data passed into the <script> block. (CVE-2026-39826)

OpenTelemetry-Go is the Go implementation of OpenTelemetry. Prior to 1.43.0, the otlp HTTP exporters (traces/metrics/logs) read the full HTTP response body into an in-memory bytes.Buffer without a size cap.
This is exploitable for memory exhaustion when the configured collector endpoint is attacker-controlled (or a network attacker can mitm the exporter connection). This vulnerability is fixed in 1.43.0.
(CVE-2026-39882)

Integer Overflow or Wraparound vulnerability in Apache Thrift TFramedTransport Go language implementation

This issue affects Apache Thrift: before 0.23.0.

Users are recommended to upgrade to version 0.23.0, which fixes the issue. (CVE-2026-41602)

Pathological inputs could cause DoS through consumePhrase when parsing an email address according to RFC 5322. (CVE-2026-42499)

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 amazon-cloudwatch-agent' or or 'yum update --advisory ALAS2-2026-3323' to update your system.

Plugin Details

Severity: Critical

ID: 319860

File Name: al2_ALAS-2026-3323.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 6/8/2026

Updated: 6/8/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-27143

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:amazon-cloudwatch-agent, cpe:/o:amazon:linux:2

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/8/2026

Vulnerability Publication Date: 3/26/2026

Reference Information

CVE: CVE-2026-27143, CVE-2026-27144, CVE-2026-32280, CVE-2026-32281, CVE-2026-32282, CVE-2026-32283, CVE-2026-32287, CVE-2026-32288, CVE-2026-32289, CVE-2026-33811, CVE-2026-33814, CVE-2026-39820, CVE-2026-39823, CVE-2026-39825, CVE-2026-39826, CVE-2026-39882, CVE-2026-41602, CVE-2026-42499

IAVB: 2026-B-0089-S, 2026-B-0120

Detections

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