# Improper input validation in Genians Genian NAC V4.0 and others

CVE record · `CVE-2026-16520`

- **Identifiers:** `CVE-2026-16520`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **CNA:** FSI
- **Weakness (CWE):** [CWE-20](https://cwe.mitre.org/data/definitions/20.html) · [CWE-202](https://cwe.mitre.org/data/definitions/202.html)
- **Tags:** [CWE-20](https://agentprime.io/advisories/tag/cwe-20.md) · [CWE-202](https://agentprime.io/advisories/tag/cwe-202.md)
- **Technologies:** [Genians Genian NAC V4.0](https://agentprime.io/advisories/technology/genians-genian-nac-v4-0.md) · [Genians Genian NAC V5.0](https://agentprime.io/advisories/technology/genians-genian-nac-v5-0.md) · [Genians Genian ZTNA V6.0](https://agentprime.io/advisories/technology/genians-genian-ztna-v6-0.md)
- **Published:** 20 Aug 2026
- **Updated:** 21 Aug 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: FSI) at 20 Aug 2026, 23:57 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Genians. Product: Genian NAC V4.0.
  - affected: `4.0.0 to before 4.0.175(Revision 150340)` (custom)
  - Other versions: unaffected
- Vendor: Genians. Product: Genian NAC V5.0.
  - affected: `5.0.0 to before 5.0.65 LTS(Revision 150331)` (custom)
  - affected: `5.0.0 to before 5.0.75 LTS(Revision 150330)` (custom)
  - affected: `5.0.0 to before 5.0.87 Release Stable(Revision 150329)` (custom)
  - affected: `5.0.0 to before 5.0.88(Revision 150328)` (custom)
  - Other versions: unaffected
- Vendor: Genians. Product: Genian ZTNA V6.0.
  - affected: `6.0.0 to before 6.0.26 LTS(Revision 150337)` (custom)
  - affected: `6.0.0 to before 6.0.35 LTS(Revision 150336)` (custom)
  - affected: `6.0.0 to before 6.0.47 Release Stable(Revision 150334)` (custom)
  - affected: `6.0.0 to before 6.0.48(Revision 150333)` (custom)
  - Other versions: unaffected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 8.7 High, CVSS 4.0: `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`, from CNA (FSI)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0054, the 45th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 20 Aug 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-16520](https://www.cve.org/CVERecord?id=CVE-2026-16520)
- [NVD: CVE-2026-16520](https://nvd.nist.gov/vuln/detail/CVE-2026-16520)

### References from the CNA

- <https://docs.genians.com/release/ko/advisories/GN-SA-2026-003.html>
- <https://github.com/genians/security-research/security/advisories/GHSA-f6f5-wx2h-ccfw>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-16520>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-16520/>. Everything for agents: <https://agentprime.io/llms.txt>.