5.9

CVE-2026-17539: hitachi energy rtu500 series cmu firmware NULL Pointer Dereference

CVSS: 5.9v3.1MediumAwaiting analysis
Published 03-09-2026Last modified 03-09-2026
Open JSON

Vulnerability summary

CVE-2026-17539 is a medium (CVSS 5.9) NULL Pointer Dereference vulnerability in hitachi energy rtu500 series cmu firmware. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.7% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.27%
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. 03-09-2026
    PublishedVulnerability first disclosed.
  2. 03-09-2026
    Last modifiedVulnerability information updated.

Description

RTU500 has a vulnerability, where high-load scenarios, such as sending GI requests at short intervals, may cause a NULL pointer dereference in the last entry of the enhanced message queue. This can cause a BCI_IEC104 fatal write error, resulting in connection interruption and restart, and ultimately a denial of service for bidirectional IEC 60870-5-104 communication.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.27%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

-0.08 pp

From 0.35% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.27%

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, ≤ 13.8.2

1 vendor · 1 product

References

1 links