CVE-2025-3756

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A vulnerability exists in the command handling of the IEC 61850 communication stack included in the product revisions li

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.

MEDIUM · CVSS 6.5 EPSS 0.00027

EPSS exploitation odds0.03% · top 91%

Monitor

No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence

No Sigma yet — build one → YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2025-3756, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

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Severity & exploitation scoring

View on NVD →

CVSS base score

6.5

MEDIUMCVSS v3.1 · [email protected]

EPSS exploitation probability

0.03%

Top 91%odds of exploitation in the next 30 days

CVSS metric silhouette

shape grows toward worst-case

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Tech impact

partial

CVSS vector breakdown

Exploitability - how they get in

Attack Vector

Network Adjacent Local Physical

Attack Complexity

Low High

Privileges Required

None Low High

User Interaction

None Required

Scope

Unchanged Changed

Impact - what breaks

Confidentiality

None Low High

Integrity

None Low High

Availability

None Low High

VECTORCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Lifecycle

13 Apr 2026Published to NVD
17 Apr 2026Last modified

Every entry is a recorded date - NVD publish/modify, CISA KEV add, public exploit disclosure. No inferred events.

View attack path from CVE-2025-3756

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ATT&CK techniques

Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.

T1210 · Exploitation of Remote Services

▤ Build a SIEM detection for these techniques

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Weakness Classification

CWE-1284Improper Validation of Specified Quantity in Input

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Related CVEs

CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.

CVE-2008-1440 Microsoft Windows XP SP2 and SP3, and Server 2003 SP1 and SP2, does not properly... same CWE-1284 CVE-2008-2374 src/sdp.c in bluez-libs 3.30 in BlueZ, and other bluez-libs before 3.34 and blue... same CWE-1284 CRITICAL CVE-2009-4488 Varnish 2.0.6 writes data to a log file without sanitizing non-printable charact... same CWE-1284 CRITICAL CVE-2010-3904 The rds_page_copy_user function in net/rds/page.c in the Reliable Datagram Socke... same CWE-1284 HIGH

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Vendor Advisories

cisa-csafcisa-csaf-csaf_files-OT-white-2026-icsa-26-120-01

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://search.abb.com/library/Download.aspx?DocumentID=7PAA020125&LanguageCode=en&DocumentPartId=&Action=Launch