Cyber Resilience

CVE-2026-2459

Hitachienergy Reb500 Firmware ≤ 8.3.3.0

Published
24 February 2026
Modified
06 April 2026
Patch / advisory
View advisory
CVSS Score v4 7.4
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0033 26th percentile
Risk Priority 28 floored blend · peak EPSS

Summary

CVE-2026-2459 is a high-severity Privilege Defined With Unsafe Actions (CWE-267) vulnerability in Hitachienergy Reb500 Firmware. Its CVSS base score is 7.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Access Token Manipulation (T1134); ranked at the 26th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-6 (Least Privilege) and AC-5 (Separation of Duties) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-2459 is a privilege management vulnerability (CWE-267) in the REB500 product from Hitachi Energy. It enables an authenticated user with the Installer role to access and alter contents of directories that this role is not authorized to reach. The vulnerability carries a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N) and was published on 2026-02-24.

An attacker requires network access and valid credentials for an Installer role account to exploit this issue, which demands low complexity and no user interaction. Exploitation grants high-impact unauthorized read access to confidential information (C:H) and modification of data integrity (I:H), with no denial-of-service effect (A:N).

Mitigation details are available in the Hitachi Energy advisory at https://publisher.hitachienergy.com/preview?DocumentID=8DBD000217&LanguageCode=en&DocumentPartId=&Action=Launch.

EU & UK References

Vulnerability Data

A vulnerability exists in REB500 for an authenticated user with Installer role to access and alter the contents of directories that the role is not authorized to do so.

CWE(s)
CWE-267

Related Threats

MITRE ATT&CK Enterprise Techniques

T1134 Access Token Manipulation Stealth
Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1548.001 Setuid and Setgid Privilege Escalation
An adversary may abuse configurations where an application has the setuid or setgid bits set in order to get code running in a different (and possibly more privileged) user’s context.
attack.mitre.org →
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
attack.mitre.org →
T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1123 Audio Capture Collection
An adversary can leverage a computer's peripheral devices (e.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-2460Same product: Hitachienergy Reb500
CVE-2025-39202Same vendor: Hitachienergy
CVE-2026-29646Shared CWE-267
CVE-2026-0945Shared CWE-267
CVE-2025-62588Shared CWE-267
CVE-2025-62589Shared CWE-267
CVE-2026-23526Shared CWE-267
CVE-2025-47811Shared CWE-267
CVE-2025-62591Shared CWE-267
CVE-2025-7691Shared CWE-267

Affected Assets

hitachienergy
reb500 firmware
≤ 8.3.3.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 10 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V13.2.2
  • V3.7.3
  • V9.2.2
  • V9.2.3

Mitigating Controls (NIST 800-53 r5) AI

AC-6 Least Privilege good match

Least privilege directly requires that privileges grant only the minimal actions needed, preventing definition of overly broad privileges that include unintended unsafe operations.

AC-5 Separation of Duties partial match

Separation of duties splits high-risk actions across multiple privileges so that no single privilege can perform the full unsafe sequence.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining and enforcing least-privilege permissions directly reduces the chance that a privilege permits unintended unsafe actions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.18 Use of privileged utility programs mostly match
mitigates

Use of privileged utility programs restricts dangerous tools but does not address unsafe actions within assigned privileges.

A.5.15 Access control partial match
mitigates

Access control policy can limit unsafe privilege use but does not define safe actions for each privilege.

A.5.18 Access rights partial match
degrades

Access rights assignment can restrict privileges to intended actions, yet does not guarantee the privilege itself is safe.

A.5.3 Segregation of duties partial match
mitigates

Segregation of duties reduces risk of unsafe actions by splitting privileges but does not address unsafe privilege definitions.

A.8.2 Privileged access rights partial match
mitigates

Privileged access rights control can restrict unsafe privileges, yet does not ensure the privilege definition itself is safe.

A.8.25 Secure development life cycle partial match
mitigates

Secure development lifecycle can catch unsafe privilege definitions during design but does not prevent them at runtime.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 9 (1 rule)
  • V-271725 OL 9 must require users to provide a password for privilege escalation. prevents CWE-267
Ubuntu 22.04 (3 rules)
  • V-260470 Ubuntu 22.04 LTS, when booted, must require authentication upon booting into single-user and maintenance modes. prevents CWE-267
  • V-260529 Ubuntu 22.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. prevents CWE-267
  • V-260542 Ubuntu 22.04 LTS must prevent direct login into the root account. prevents CWE-267

References