Detections
Analytics
Amazon Linux 2023 : nginx-mod-njs (ALAS2023-2026-3300)
high Nessus Plugin ID 371860
Synopsis
The remote Amazon Linux 2023 host is missing a security update.Description
It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3300 advisory.DescriptionNGINX JavaScript (njs) has a vulnerability where the njs XML module exposes entity-backed XML attributes inconsistently with libxml2 canonicalization. In both the built-in njs and QuickJS backends during the canonicalization process, the $attr$Name getter may return undefined for an explicitly present attribute containing an internal entity reference. The $attrs getter may return a value derived only from the first attribute child. This may allow an unauthenticated attacker that invests significant effort in obtaining a genuinely signed document to skip validation while signature verification succeeds. An nginx- saml deployment is a confirmed affected consumer when run with the built-in njs backend.
ImpactIn affected signed-XML consumers, an unauthenticated attacker can cause security-relevant attributes to appear absent or truncated while signature verification succeeds. In nginx-saml, this can bypass expiry, Destination, and request-correlation checks, enabling replay or acceptance of a response outside its intended context. It does not permit signature or identity forgery, or a direct availability impact.
There is no control plane exposure; this is a data plane issue only.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
(CVE-2026-101019)
Description
NGINX JavaScript (njs) has a vulnerability where the built-in njs engine leaks a libxml2 parser context when xml.parse() fails. The failure path did not register cleanup and the context was not released for the lifetime of the process. An unauthenticated attacker may send requests with malformed XML and can cause unbounded memory growth in long-lived NGINX worker processes.
Impact
This vulnerability may allow remote attackers to send requests that trigger repeated parsing of malformed XML and may lead to NGINX worker termination or denial of service. There is no control plane exposure;
this is a data plane issue only.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
(CVE-2026-101025)
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 nginx-mod-njs --releasever 2023.12.20261026' or or 'dnf update --advisory ALAS2023-2026-3300 --releasever 2023.12.20261026' to update your system.See Also
https://alas.aws.amazon.com//AL2023/ALAS2023-2026-3300.html
https://alas.aws.amazon.com/faqs.html
Plugin Details
Severity: High
ID: 371860
File Name: al2023_ALAS2023-2026-3300.nasl
Version: 1.1
Type: Local
Agent: unix
Published: 10/25/2026
Updated: 10/25/2026
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: Low
Score: 3.5
Percentile: 51.45
CVSS v2
Risk Factor: Medium
Base Score: 6.1
Temporal Score: 4.5
Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:P/A:N
CVSS Score Source: CVE-2026-101019
CVSS v3
Risk Factor: Medium
Base Score: 6.5
Temporal Score: 5.7
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
CVSS v4
Risk Factor: High
Base Score: 8.3
Threat Score: 4.8
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
Vulnerability Information
CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:nginx-mod-njs-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-njs-debugsource, p-cpe:/a:amazon:linux:nginx-mod-njs
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 10/24/2026
Vulnerability Publication Date: 10/14/2026