What is CVE-2026-31851?

CVE-2026-31851 is a critical-severity vulnerability in Nexxt Solutions Nebula 300+, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2026-03-23.

How severe is CVE-2026-31851?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Nexxt Solutions Nebula 300+

CVE-2026-31851

Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 does not implement rate limiting or account lockout mechanisms on authentication interfaces. An attacker can perform unlimited authentication attempts against endpoints that rely on credential validation, enabling brute-force attacks to guess administrative credentials without restriction.

EPSS: 0.003 (25.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Nexxt Solutions Nebula 300+ — versions <= 12.01.01.37
Nexxtsolutions Nebula300plus
Nexxtsolutions Nebula300plus_firmware

Weakness classification (CWE)

CWE-307 — Improper Restriction of Excessive Authentication Attempts

References

309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c (Product, third-party-advisory)
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c (Product, third-party-advisory)

Frequently asked questions

What is CVE-2026-31851?: CVE-2026-31851 is a critical-severity vulnerability in Nexxt Solutions Nebula 300+, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2026-03-23.
How severe is CVE-2026-31851?: Critical severity. CVSS v3 base score is 9.8 out of 10.