CyberSecBulletin
CVE-2026-16520NVD status: Deferred

Improper input validation and Exposure of sensitive information through data queries…

Published Updated By the CyberSecBulletin desk

CVE-2026-16520 is a high-severity improper input validation vulnerability in Genian NAC V4.0 from Genians, with a CVSS 4.0 base score of 8.7 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 4.0.175(Revision 150340) as the first without the flaw, so updating Genian NAC V4.0 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Genian NAC V4.0 to 4.0.175(Revision 150340) or a later version.
  2. Update Genian NAC V5.0 to 5.0.65 LTS(Revision 150331) or 5.0.75 LTS(Revision 150330) or 5.0.87 Release Stable(Revision 150329) or 5.0.88(Revision 150328), whichever matches your release line, or a later version.
  3. Update Genian ZTNA V6.0 to 6.0.26 LTS(Revision 150337) or 6.0.35 LTS(Revision 150336) or 6.0.47 Release Stable(Revision 150334) or 6.0.48(Revision 150333), whichever matches your release line, or a later version.
  4. Read the advisory on github.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
GeniansGenian NAC V4.04.0.0 up to, but not including, 4.0.175(Revision 150340)4.0.175(Revision 150340)
GeniansGenian NAC V5.05.0.0 up to, but not including, 5.0.65 LTS(Revision 150331); 5.0.0 up to, but not including, 5.0.75 LTS(Revision 150330); 5.0.0 up to, but not including, 5.0.87 Release Stable(Revision 150329); 5.0.0 up to, but not including, 5.0.88(Revision 150328)5.0.65 LTS(Revision 150331), 5.0.75 LTS(Revision 150330), 5.0.87 Release Stable(Revision 150329), 5.0.88(Revision 150328)
GeniansGenian ZTNA V6.06.0.0 up to, but not including, 6.0.26 LTS(Revision 150337); 6.0.0 up to, but not including, 6.0.35 LTS(Revision 150336); 6.0.0 up to, but not including, 6.0.47 Release Stable(Revision 150334); 6.0.0 up to, but not including, 6.0.48(Revision 150333)6.0.26 LTS(Revision 150337), 6.0.35 LTS(Revision 150336), 6.0.47 Release Stable(Revision 150334), 6.0.48(Revision 150333)

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
NoneNo loss of integrity on the vulnerable system.
Availability (vulnerable system)
NoneNo loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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. Scored by CNA.

Official description

Improper input validation and Exposure of sensitive information through data queries vulnerability in Genians Genian NAC V4.0, Genians Genian NAC V5.0, and Genians Genian ZTNA V6.0 allows SQL Injection and Authentication Bypass. This issue affects Genian NAC V4.0: from 4.0.0 before 4.0.175(Revision 150340); Genian NAC V5.0: from 5.0.0 before 5.0.65 LTS(Revision 150331), from 5.0.0 before 5.0.75 LTS(Revision 150330), from 5.0.0 before 5.0.87 Release Stable(Revision 150329), and from 5.0.0 before 5.0.88(Revision 150328); Genian ZTNA V6.0: from 6.0.0 before 6.0.26 LTS(Revision 150337), from 6.0.0 before 6.0.35 LTS(Revision 150336), from 6.0.0 before 6.0.47 Release Stable(Revision 150334), and from 6.0.0 before 6.0.48(Revision 150333).

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Genian NAC V4.0

All Genian NAC V4.0 vulnerabilities

Recent Improper Input Validation vulnerabilities

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