Heap-based Buffer Overflow Affecting nginx package, versions <1:1.30.2-1.amzn2023.0.1


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
9.96% (96th percentile)

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  • Snyk IDSNYK-AMZN2023-NGINX-17289991
  • published10 Jun 2026
  • disclosed22 May 2026

Introduced: 22 May 2026

CVE-2026-9256  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 nginx to version 1:1.30.2-1.amzn2023.0.1 or higher.
This issue was patched in ALAS2023-2026-1773.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nginx package and not the nginx package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1