AC500 V2 unauthenticated crafter packet vulnerability

published 2021-02-09 5y ago modified 2026-06-17 4mo ago also EUVD-2020-17399

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.6%; EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits: 0; none known

An unauthenticated specially crafted packet sent by an attacker over the network will cause a denial-of-service (DoS) vulnerability. Vulnerability allows attacker to stop the PLC. After stopping (ERR LED flashing red), physical access to the PLC is required in order to restart the application. This issue affects: ABB AC500 V2 products with onboard Ethernet version 2.8.4 and prior versions.

Patch / fix

fixed in 1 links 1

abb ac500_cpu_firmware 2.8.5

search.abb.com/library/Download.aspx?DocumentID=3ADR010667&LanguageCode=e… advisory

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Exploit prediction

1.63% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

ABB AC500 V2 products with onboard Ethernet

Classification

Weakness

CWE-789 Memory Allocation with Excessive Size Value
CWE-770 Allocation of Resources Without Limits or Throttling

References

search.abb.com /library/Download.aspx?DocumentID=3ADR010667&LanguageCode=en&DocumentPartId=&Action=Launch
patch, vendor-advisory

Sources

CVE List CVE-2020-24685
NVD CVE-2020-24685

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