Amazon Linux 2023 : credentials-fetcher (ALAS2023-2026-1885)

critical Nessus Plugin ID 322109

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1885 advisory.

Parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.
(CVE-2026-25680)

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
(CVE-2026-25681)

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
(CVE-2026-27136)

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, .) to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates. (CVE-2026-27145)

The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII- only label. For example, ToUnicode(xn--example-.com) incorrectly returns the name example.com rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject example.com but permit xn--example-.com. If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name example.com. (CVE-2026-39821)

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
(CVE-2026-42502)

Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU. (CVE-2026-42504)

Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
(CVE-2026-42506)

When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.
(CVE-2026-42507)

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 'dnf update credentials-fetcher --releasever 2023.12.20260622' or or 'dnf update --advisory ALAS2023-2026-1885 --releasever 2023.12.20260622' to update your system.

Plugin Details

Severity: Critical

ID: 322109

File Name: al2023_ALAS2023-2026-1885.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 6/22/2026

Updated: 6/22/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.1

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-2026-39821

CVSS v3

Risk Factor: Critical

Base Score: 9.6

Temporal Score: 8.3

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:credentials-fetcher, cpe:/o:amazon:linux:2023

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

Exploit Ease: No known exploits are available

Patch Publication Date: 6/22/2026

Vulnerability Publication Date: 5/12/2026

Reference Information

CVE: CVE-2026-25680, CVE-2026-25681, CVE-2026-27136, CVE-2026-27145, CVE-2026-39821, CVE-2026-42502, CVE-2026-42504, CVE-2026-42506, CVE-2026-42507

IAVB: 2026-B-0120, 2026-B-0146

Detections

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