Detections
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Amazon Linux 2023 : nginx, nginx-all-modules, nginx-core (ALAS2023-2026-3263)

critical Nessus Plugin ID 371840

Synopsis

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

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3263 advisory.

 A vulnerability exists in NGINX Plus and NGINX Open Source when a location is configured that uses the alias directive together with rewrite and a set or return directive referencing the $request_filename variable. Alternatively, the same result could be achieved when the $request_filename variable is used in an access log format directive. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

 Impact:This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. 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-2026-15176)

 A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and the root directive or access log format references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

 Impact:This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. 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-2026-93479)

 DescriptionNGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module. When using HTTP/3 with

 proxy_request_buffering on directive, an unauthenticated attacker may be able to inject data in the proxied request.

 Impact

 This vulnerability may allow remote attackers to

 inject data in the proxied request. 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-2026-95101)

 NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_core_module module. When asynchronous file I/O (AIO) is enabled in certain configurations, processing a Server Side Includes (SSI) page containing include virtual commands may trigger a Use-After-Free (UAF) in the NGINX worker process.
 This may cause memory corruption or a worker process crash. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

 Impact:This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system, corrupt its memory, or possibly trigger code execution. 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-2026-97205)

 DescriptionWhen NGINX Plus or NGINX Open Source is configured with ssl_session_cache

 shared:name:size

 without an explicit ssl_session_ticket_key file directives to automatically rotate SSL session ticket keys, a remote unauthenticated attacker is able to forge client SSL sessions

 in a non-deterministic manner that is beyond the attacker's control. An attacker could leverage this vulnerability to bypass verification of client certificates.

 Impact

 This vulnerability can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with access to sensitive information. 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-2026-97629)

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 --releasever 2023.12.20261026' or or 'dnf update --advisory ALAS2023-2026-3263 --releasever 2023.12.20261026' to update your system.

See Also

https://alas.aws.amazon.com//AL2023/ALAS2023-2026-3263.html

https://alas.aws.amazon.com/faqs.html

https://explore.alas.aws.amazon.com/CVE-2026-15176.html

https://explore.alas.aws.amazon.com/CVE-2026-93479.html

https://explore.alas.aws.amazon.com/CVE-2026-95101.html

https://explore.alas.aws.amazon.com/CVE-2026-97205.html

https://explore.alas.aws.amazon.com/CVE-2026-97629.html

Plugin Details

Severity: Critical

ID: 371840

File Name: al2023_ALAS2023-2026-3263.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 10/25/2026

Updated: 10/25/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.9

Percentile: 99.33

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 6

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

CVSS Score Source: CVE-2026-97205

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.3

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 8.2

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:nginx-all-modules, p-cpe:/a:amazon:linux:nginx-core-debuginfo, p-cpe:/a:amazon:linux:nginx-core, p-cpe:/a:amazon:linux:nginx-debuginfo, p-cpe:/a:amazon:linux:nginx-debugsource, p-cpe:/a:amazon:linux:nginx-filesystem, p-cpe:/a:amazon:linux:nginx-mod-devel, p-cpe:/a:amazon:linux:nginx-mod-http-image-filter-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-http-image-filter, p-cpe:/a:amazon:linux:nginx-mod-http-perl-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-http-perl, p-cpe:/a:amazon:linux:nginx-mod-http-xslt-filter-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-http-xslt-filter, p-cpe:/a:amazon:linux:nginx-mod-mail-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-mail, p-cpe:/a:amazon:linux:nginx-mod-stream-debuginfo, p-cpe:/a:amazon:linux:nginx-mod-stream, p-cpe:/a:amazon:linux:nginx

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: 10/24/2026

Vulnerability Publication Date: 10/14/2026

Reference Information

CVE: CVE-2026-15176, CVE-2026-93479, CVE-2026-95101, CVE-2026-97205, CVE-2026-97629

IAVA: 2026-A-1142