CISA 2026-07-07

Hitachi Energy e-mesh EMS

CVE-2026-42945

Machine-generated analysis · WAYSCloud LLM

The vulnerability stems from NGINX components in e-mesh EMS using versions v1.30.0 or below, where specific rewrite rule configurations can trigger a heap buffer overflow.

Context

Hitachi Energy e-mesh EMS is an energy management system used in the energy sector. The advisory states that a heap-based buffer overflow exists in the NGINX ngx_http_rewrite_module due to improper handling of PCRE captures in rewrite directives. Exploitation could lead to denial of service via application restart and potentially arbitrary code execution under specific conditions. The advisory explicitly notes that systems with ASLR disabled or where ASLR can be bypassed are more susceptible.

Operator considerations

Check: Inventory e-mesh EMS instances running versions 4.1.6, 4.4.2, or 4.7.0. Patch: Apply the vendor-released hotfix to update NGINX to v1.30.2 or later. Log: Monitor HTTP request logs for unusual patterns involving rewrite directives and PCRE captures.

From Cybersecurity and Infrastructure Security Agency ↗

Hitachi Energy is aware of a buffer overflow vulnerability that affects e-mesh EMS product versions listed in this document. Successful exploitation of this vulnerability could lead to a buffer overflow condition, potentially resulting in application outages (denial of service) and possible arbitrary code execution. Please refer to the Recommended Immediate Actions for information about the mitigation/remediation.

The following versions of Hitachi Energy e-mesh EMS are affected:

Hitachi Energy e-mesh EMS 4.1.6, 4.4.2, 4.7.0

Vendor

Equipment

Hitachi Energy

Hitachi Energy e-mesh EMS

Heap-based Buffer Overflow

Critical Infrastructure Sectors: Energy

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Switzerland

NGINX Plus and NGINX Open Source used in e-mesh EMS have a vulnerability in the ngx_http_rewrite_module module. This vulnerability exists when the rewri...

Read the full advisory on CISA →