Reversible ecos_pw Cookie Allows Authentication Bypass in Nexxt Nebula 300+
Summary
| CVE | CVE-2026-31848 |
|---|---|
| State | PUBLISHED |
| Assigner | TuranSec |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-23 13:16:30 UTC |
| Updated | 2026-04-29 17:45:08 UTC |
| Description | Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 uses the ecos_pw cookie for authentication, which contains Base64-encoded credential data combined with a static suffix. Because the encoding is reversible and lacks integrity protection, an attacker can reconstruct or forge a valid cookie value without proper authentication. This allows unauthorized administrative access to protected endpoints. |
Risk And Classification
Primary CVSS: v4.0 8.7 HIGH from 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.000570000 probability, percentile 0.177130000 (date 2026-05-02)
Problem Types: CWE-312 | CWE-312 CWE-312 Cleartext Storage of Sensitive Information
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | Secondary | 8.7 | HIGH | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 8.7 | HIGH | CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v4.0 Breakdown
Attack Vector
AdjacentAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
NoneConfidentiality
HighIntegrity
HighAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Hardware | Nexxtsolutions | Nebula300plus | - | All | All | All |
| Operating System | Nexxtsolutions | Nebula300plus Firmware | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Nexxt Solutions | Nebula 300 | affected <= 12.01.01.37 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.nexxtsolutions.com/connectivity/internal-products/ARN02304U6 | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | www.nexxtsolutions.com | Product |
| nexxt-connectivity-frontend.s3.amazonaws.com/media/docs/Nebula300+_v12.01.01.37.zip | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | nexxt-connectivity-frontend.s3.amazonaws.com | Product |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Angel Barre (call4pwn) (en)
There are currently no legacy QID mappings associated with this CVE.