6.9

CVE-2026-8479: hitachi energy rtu500 series cmu firmware NULL Pointer Dereference

CVSS: 6.9v4.0MediumDeferred
Published 26-05-2026Last modified 26-05-2026
Open JSON

Vulnerability summary

CVE-2026-8479 is a medium (CVSS 6.9) NULL Pointer Dereference vulnerability in hitachi energy rtu500 series cmu firmware. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.1% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.25%
0%100%
Low · +0.08 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 26-05-2026
    PublishedVulnerability first disclosed.
  2. 26-05-2026
    Last modifiedVulnerability information updated.

Description

IEC 60870-5-104 used in bidirectional mode in RTU500 is vulnerable for a NULL pointer dereferencing, if a specially crafted sequence of messages is sent for a certain time, causing Denial of Service impact. Product is only affected if IEC 60870-5-104 functionality in bidirectional mode (BCI) is configured.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

+0.08 pp

From 0.17% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Hitachi energy1 product
  • rtu500 series cmu firmware≥ 12.7.1, ≤ 12.7.7 | ≥ 13.5.1, ≤ 13.5.4 | ≥ 13.6.1, ≤ 13.6.3 | ≥ 13.7.1, ≤ 13.7.8 | 13.8.1

1 vendor · 1 product

References

1 links