Archive for May 27, 2023

Zyxel Warns Of Critical Vulnerabilities In Firewall And VPN Devices

Posted in Commentary with tags on May 27, 2023 by itnerd

Zyxel is warning customers of two critical-severity vulnerabilities in several of its firewall and VPN products. Unpatched, a threat actor could leverage the vulnerability without authentication. Here are the vulnerabilities:

CVE-2023-33009

A buffer overflow vulnerability in the notification function in some firewall versions could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device. 

CVE-2023-33010

A buffer overflow vulnerability in the ID processing function in some firewall versions could allow an unauthenticated attacker to cause DoS conditions and even a remote code execution on an affected device. 

Here’s a list of affected devices:

  • Zyxel ATP firmware versions ZLD V4.32 to V5.36 Patch 1 (fixed in ZLD V5.36 Patch 2)
  • Zyxel USG FLEX firmware versions ZLD V4.50 to V5.36 Patch 1 (fixed in ZLD V5.36 Patch 2)
  • Zyxel USG FLEX50(W) / USG20(W)-VPN firmware versions ZLD V4.25 to V5.36 Patch 1 (fixed in ZLD V5.36 Patch 2)
  • Zyxel VPN firmware versions ZLD V4.30 to V5.36 Patch 1 (fixed in ZLD V5.36 Patch 2)
  • Zyxel ZyWALL/USG firmware versions ZLD V4.25 to V4.73 Patch 1 (fixed in ZLD V4.73 Patch 2)

Zyxel has released patches for their firewalls. I’d strongly suggest installing them ASAP.

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