CVE-2021-26622 [Critical] | Input Validation Bypass in Genian Nac

An remote code execution vulnerability due to SSTI vulnerability and insufficient file name parameter validation was discovered in Genian NAC. Remote attackers are able to execute arbitrary malicious code with SYSTEM privileges on all connected nodes in NAC through this vulnerability.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	3.84%	2.85%	-0.99%
2	2026-03-18	2.27%	3.84%	+1.56%
3	2025-11-21	—	2.27%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

3.84%

2.85%

-0.99%

2026-03-18

2.27%

3.84%

+1.56%

2025-11-21

—

2.27%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.6	3.1	CRITICAL	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. 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:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. 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.	2.8	6.0	[email protected]
10.0	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. 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	6.0	[email protected]
10.0	2.0	HIGH	`AV:N/AC:L/Au:N/C:C/I:C/A:C` 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:C) Complete confidentiality impact. Integrity impact (I:C) Complete integrity impact. Availability impact (A:C) Complete availability impact.	10.0	10.0	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.6

3.1

CRITICAL

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

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
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:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
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.

2.8

6.0

[email protected]

10.0

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
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

6.0

[email protected]

10.0

2.0

HIGH

AV:N/AC:L/Au:N/C:C/I:C/A:C 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:C): Complete confidentiality impact.
Integrity impact (I:C): Complete integrity impact.
Availability impact (A:C): Complete availability impact.

10.0

[email protected]

Affected software / configurations for CVE-2021-26622

Vendor	Product	Version	Raw CPE
genians	genian_nac	>= 4.0, <= 4.0.145.0831	cpe:2.3:a:genians:genian_nac::::::::
genians	genian_nac	>= 5.0, <= 5.0.42.0827	cpe:2.3:a:genians:genian_nac::::::::

References for CVE-2021-26622

URL	Tags
https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=66580	Broken Link Third Party Advisory

URL

CVE-2021-26622 | Genian NAC remote code execution vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2021-26622

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26622

Weakness enumeration for CVE-2021-26622

Affected software / configurations for CVE-2021-26622

References for CVE-2021-26622