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Fencer Vulns
medium 6.5

CVE-2025-3756 json

Denial of Service Vulnerabilities in System 800xA, Symphony® Plus IEC 61850

published 2026-04-13 6 mo ago modified 2026-10-14 25 d ago also EUVD-2025-209425

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

A vulnerability exists in the command handling of the IEC 61850 communication stack included in the product revisions listed as affected in this CVE. An attacker with access to IEC 61850 networks could exploit the vulnera bility by using a specially crafted 61850 packet, forcing the communication interfaces of the PM 877, CI850 and CI868 modules into fault mode or causing unavailability of the S+ Operations 61850 connectivity, resulting in a denial-of-service situation.

The System 800xA IEC61850 Connect is not affected. Note: This vulnerability does not impact on the overall availability and functionality of the S+ Operations node, only the 61850 communication function.

This issue affects AC800M (System 800xA): from 6.0.0x through 6.0.0303.0, from 6.1.0x through 6.1.0031.0, from 6.1.1x through 6.1.1004.0, from 6.1.1x through 6.1.1202.0, from 6.2.0x through 6.2.0006.0; Symphony Plus SD Series: A_0, A_1, A_2.003, A_3.005, A_4.001, B_0.005; Symphony Plus MR (Melody Rack): from 3.10 through 3.52; S+ Operations: 2.1, 2.2, 2.3, 3.3.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-26-120-01 updated cvss 6.5

ABB System 800xA, Symphony Plus IEC 61850

  • ABB AC800M Product line (System 800xA) Firmware ABB PM 877 Firmware >=3.10, <=3.52 ABB S+ Operations Firmware 2.1, Firmware 2.2, Firmware 2.3, Firmware 3.3 ABB Symphony Plus SD Series Firmware A_0, Firmware A_1, Firmware A_2.003, Firmware A_3.005, Firmware A_4.001, Firmware B_0.005
    affected: vendor fix, workaround, mitigation
  • ABB AC800M Product line (System 800xA) Firmware 3, Firmware 7.0 ABB PM 877 Firmware 3.53 ABB S+ Operations Firmware 3.4 ABB Symphony Plus SD Series Firmware C_0
    fixed

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Affected products

  • ABB AC800M (System 800xA)
  • ABB Symphony Plus SD Series
  • ABB Symphony Plus MR (Melody Rack)
  • ABB S+ Operations

Classification

Weakness
  • CWE-1284 Improper Validation of Specified Quantity in Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.