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Amazon Linux 2 : nginx, --advisory ALAS2NGINX1-2026-013 (ALASNGINX1-2026-013)

critical Nessus Plugin ID 319833

Synopsis

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

Description

The version of nginx installed on the remote host is prior to 1.30.2-1. It is, therefore, affected by a vulnerability as referenced in the ALAS2NGINX1-2026-013 advisory.

 NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when a rewrite directive uses a regex pattern with distinct, overlapping Perl- Compatible Regular Expression (PCRE) captures (for example, ^/((.*))$) and a replacement string that references multiple such captures (for example, $1$2) in a redirect or arguments context. 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated. (CVE-2026-9256)

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

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

Solution

Run 'yum update nginx' or or 'yum update --advisory ALAS2NGINX1-2026-013' to update your system.

See Also

https://alas.aws.amazon.com//AL2/ALAS2NGINX1-2026-013.html

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

https://explore.alas.aws.amazon.com/CVE-2026-9256.html

Plugin Details

Severity: Critical

ID: 319833

File Name: al2_ALASNGINX1-2026-013.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 6/8/2026

Updated: 6/8/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 8.4

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-2026-9256

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:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:nginx, p-cpe:/a:amazon:linux:nginx-core, p-cpe:/a:amazon:linux:nginx-mod-mail, p-cpe:/a:amazon:linux:nginx-mod-http-perl, p-cpe:/a:amazon:linux:nginx-mod-stream, p-cpe:/a:amazon:linux:nginx-mod-http-image-filter, p-cpe:/a:amazon:linux:nginx-all-modules, p-cpe:/a:amazon:linux:nginx-mod-http-xslt-filter, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:nginx-debuginfo, p-cpe:/a:amazon:linux:nginx-filesystem, p-cpe:/a:amazon:linux:nginx-mod-devel, p-cpe:/a:amazon:linux:nginx-mod-http-geoip

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: 5/22/2026

Reference Information

CVE: CVE-2026-9256

IAVA: 2026-A-0515