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[ CVE-2023-33010 · Published 24 May 2023 ]

Zyxel Multiple Firewalls Buffer Overflow Vulnerability

Exploited · CISA KEV CVSS 9.8 EPSS 29%No fix listed yet

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2023-06-05
  • EPSS: 29% chance of exploitation in the next 30 days (higher than 98% of CVEs)
  • Critical severity: CVSS 9.8

[ Description ]Official description

A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

CISA: 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.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 26 Jun 2023): Apply updates per vendor instructions.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References