SB2026052055 - Remote code execution in NGINX ngx_http_js_module

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Main Vulnerability Database SB2026052055

SB2026052055 - Remote code execution in NGINX ngx_http_js_module

Published: May 20, 2026

Security Bulletin ID SB2026052055
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Heap-based buffer overflow (CVE-ID: CVE-2026-8711)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber


The vulnerability allows a remote attacker to cause a denial of service or execute arbitrary code.

The vulnerability exists due to heap-based buffer overflow in the ngx_http_js_module module when processing crafted HTTP requests that reach a location invoking ngx.fetch() with the js_fetch_proxy directive configured with at least one client-controlled NGINX variable. A remote attacker can send crafted HTTP requests to cause a denial of service or execute arbitrary code.

Code execution is possible on systems with Address Space Layout Randomization disabled. There is no control plane exposure; this is a data plane issue only.


Remediation

Install update from vendor's website.

References