⚠ Known Exploited Vulnerability (KEV) Tracker

Description

Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the ID processing function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.

Lifecycle Timeline

• 2023-05-24
  CVE published

  Entered the public CVE record.

  CVE.org →
• 2023-06-05
  Added to CISA KEV 12 days later

  Listed as known exploited, which starts the federal remediation clock.

  CISA KEV →
• 2023-06-26
  Federal remediation due 21 days later

  Deadline for federal civilian agencies under BOD 22-01 — now passed.

  CISA KEV
• 2024-07-25
  First national advisory 13 months later

  NSA — North Korea Cyber Group Conducts Global Espionage Campaign to Advance Regime’s Military and Nuclear Programs

  CyberzSOC advisory index →
• not recorded
  Public exploit code

  No dated exploit found in Metasploit, Exploit-DB or public GitHub repositories.
• not recorded
  EPSS flags exploitation risk

  Reached 10% only through a model recalibration, which moves every score at once and says nothing about this CVE.
• not recorded
  Vendor fix published

  No dated vendor fix. Only Microsoft publishes a machine-readable release date; other vendors state a fixed version without one.

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 186 points from 2023-05-27, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 81.3% on 2025-03-29.

Published Applicability

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

No mentions found in monitored research blogs or news feeds.

Detection & Exploitation

Blind spot. No public detection — verify by version/patch. Nothing in the monitored scanner, IDS, SIEM or offensive-tool collections references this CVE, so exposure has to be established from asset inventory and patch level rather than from a signature.

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

CISA Assessment (Vulnrichment / SSVC)

D3FEND Countermeasures

Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-120) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.

KEV Catalog Status

Listed By

Referenced in Advisories

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References

CVE.org record → NVD entry → CISA KEV catalog → FortiGuard Labs → Rapid7 AttackerKB →