CVE-2020-8479 [Critical] | Security Vulnerability in 800xa System

For the Central Licensing Server component used in ABB products ABB Ability™ System 800xA and related system extensions versions 5.1, 6.0 and 6.1, Compact HMI versions 5.1 and 6.0, Control Builder Safe 1.0, 1.1 and 2.0, Symphony Plus -S+ Operations 3.0 to 3.2 Symphony Plus -S+ Engineering 1.1 to 2.2, Composer Harmony 5.1, 6.0 and 6.1, Melody Composer 5.3, 6.1/6.2 and SPE for Melody 1.0SPx (Composer 6.3), Harmony OPC Server (HAOPC) Standalone 6.0, 6.1 and 7.0, ABB Ability™ System 800xA/ Advant® OCS Control Builder A 1.3 and 1.4, Advant® OCS AC100 OPC Server 5.1, 6.0 and 6.1, Composer CTK 6.1 and 6.2, AdvaBuild 3.7 SP1 and SP2, OPCServer for MOD 300 (non-800xA) 1.4, OPC Data Link 2.1 and 2.2, Knowledge Manager 8.0, 9.0 and 9.1, Manufacturing Operations Management 1812 and 1909, ABB AbilityTM SCADAvantage versions 5.1 to 5.6.5. an XML External Entity Injection vulnerability exists that allows an attacker to read or call arbitrary files from the license server and/or from the network and also block the license handling.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.71%	2.20%	+1.50%
2	2026-03-30	0.49%	0.71%	+0.22%
3	2025-11-21	—	0.49%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.71%

2.20%

+1.50%

2026-03-30

0.49%

0.71%

+0.22%

2025-11-21

—

0.49%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.4	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	3.9	5.5	[email protected]
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.4

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:L): Might cause slowdowns, glitches, or partial disruption—not a full brick.

3.9

5.5

[email protected]

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

Affected software / configurations for CVE-2020-8479

Vendor	Product	Version	Raw CPE
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:-::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:feature_pack_4::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:feature_pack_4_revision_d::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_a::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_b::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_c::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_d::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_e::::::
abb	800xa_system	5.1	cpe:2.3:a:abb:800xa_system:5.1:revision_e_feature_pack_4::::::
abb	800xa_system	6.0	cpe:2.3:a:abb:800xa_system:6.0:::::::*
abb	800xa_system	6.0.1	cpe:2.3:a:abb:800xa_system:6.0.1:::::::*
abb	800xa_system	6.0.3	cpe:2.3:a:abb:800xa_system:6.0.3:::::::*
abb	800xa_system	6.1	cpe:2.3:a:abb:800xa_system:6.1:::::::*
abb	compact_hmi	5.1	cpe:2.3:a:abb:compact_hmi:5.1:-::::::
abb	compact_hmi	5.1	cpe:2.3:a:abb:compact_hmi:5.1:feature_pack_4_revision_d::::::
abb	compact_hmi	5.1	cpe:2.3:a:abb:compact_hmi:5.1:revision_b::::::
abb	compact_hmi	5.1	cpe:2.3:a:abb:compact_hmi:5.1:revision_d::::::
abb	compact_hmi	6.0.1-1	cpe:2.3:a:abb:compact_hmi:6.0.1-1:::::::*
abb	compact_hmi	6.0.3-2	cpe:2.3:a:abb:compact_hmi:6.0.3-2:::::::*
abb	control_builder_safe	1.0	cpe:2.3:a:abb:control_builder_safe:1.0:::::::*
abb	control_builder_safe	1.1	cpe:2.3:a:abb:control_builder_safe:1.1:::::::*
abb	control_builder_safe	2.0	cpe:2.3:a:abb:control_builder_safe:2.0:::::::*

References for CVE-2020-8479

URL	Tags
https://search.abb.com/library/Download.aspx?DocumentID=2PAA121230&LanguageCode=en&DocumentPartId=&Action=Launch	Vendor Advisory
https://search.abb.com/library/Download.aspx?DocumentID=2PAA121231&LanguageCode=en&DocumentPartId=&Action=Launch	Vendor Advisory
https://search.abb.com/library/Download.aspx?DocumentID=3CCA2020-003309&LanguageCode=en&DocumentPartId=&Action=Launch

URL

CVE-2020-8479 | ABB Central Licensing System - XML External Entity Injection

Exploit prediction scoring system (EPSS) score for CVE-2020-8479

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8479

Weakness enumeration for CVE-2020-8479

Affected software / configurations for CVE-2020-8479

References for CVE-2020-8479