CVE-2021-31399
2N
- Published
- 13 August 2021
- Last modified
- 17 June 2026
- CVSS
- 5.9 v3.1
- Severity
- medium
- EPSS
- 0.8% (56th pct)
- CISA KEV
- Not listed
- NVD status
- Modified
- Weaknesses
- CWE-295
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Description
On 2N Access Unit 2.0 2.31.0.40.5 devices, an attacker can pose as the web relay for a man-in-the-middle attack.
Exploitation
Not listed in the CISA Known Exploited Vulnerabilities catalogue as of 2026.09.04. That is an absence of confirmed public exploitation, not evidence that exploitation has not occurred. EPSS models a 0.8% probability of exploitation activity in the next 30 days.
Affected products
| Product | Vendor | Type | Versions named |
|---|---|---|---|
| Access Unit 2.0 | 2N | unknown | 2.31.0.40.5 |
References
Vendor advisory and patch
- https://www.2n.cz/en_GB/products/ip-access-control/2n-access-unit-2
- https://www.2n.cz/en_GB/products/ip-access-control/2n-access-unit-2
- https://cds.thalesgroup.com/en/tcs-cert/CVE-2021-31399
- https://excellium-services.com/cert-xlm-advisory/cve-2021-31399/ third-party
- https://excellium-services.com/cert-xlm-advisory/cve-2021-31399/ third-party
Record assembled from NVD, CISA KEV 2026.09.04 and FIRST EPSS 2026-09-04. Affected products are those NVD's CPE configuration names that fall inside this site's scope; a CVE may affect products outside it.