CVE-2023-4420 [Critical] | Information Disclosure in Lms531 Firmware

A remote unprivileged attacker can intercept the communication via e.g. Man-In-The-Middle, due to the absence of Transport Layer Security (TLS) in the SICK LMS5xx. This lack of encryption in the communication channel can lead to the unauthorized disclosure of sensitive information. The attacker can exploit this weakness to eavesdrop on the communication between the LMS5xx and the Client, and potentially manipulate the data being transmitted.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.06%	0.24%	+0.19%
2	2023-08-31	0.04%	0.06%	+0.01%
3	2023-08-25	—	0.04%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.06%

0.24%

+0.19%

2023-08-31

0.04%

0.06%

+0.01%

2023-08-25

—

0.04%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
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]
7.4	3.1	HIGH	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N` 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:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. 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:N) Service keeps running; no real outage angle.	2.2	5.2	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

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]

7.4

3.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N 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:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:N): Service keeps running; no real outage angle.

2.2

5.2

[email protected]

Affected software / configurations for CVE-2023-4420

Vendor	Product	Version	Raw CPE
sick	lms531_firmware	—	cpe:2.3:o:sick:lms531_firmware::::::::
sick	lms511_firmware	—	cpe:2.3:o:sick:lms511_firmware::::::::
sick	lms500_firmware	—	cpe:2.3:o:sick:lms500_firmware::::::::

References for CVE-2023-4420

URL	Tags
https://sick.com/.well-known/csaf/white/2023/sca-2023-0007.json	Vendor Advisory
https://sick.com/.well-known/csaf/white/2023/sca-2023-0007.pdf	Vendor Advisory
https://sick.com/psirt	Vendor Advisory

URL

CVE-2023-4420

Exploit prediction scoring system (EPSS) score for CVE-2023-4420

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4420

Weakness enumeration for CVE-2023-4420

Affected software / configurations for CVE-2023-4420

References for CVE-2023-4420