CVE-2024-11667: Zyxel Multiple Firewalls Path Traversal Vulnerability

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Yes, if you run Zyxel Multiple Firewalls. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-12-03, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-12-24; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
• EPSS 2.9%, percentile 87: FIRST’s model estimates a 2.9% chance of exploitation activity in the next 30 days, higher than 87% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

What it is

A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.00 through V5.38, USG FLEX series firmware versions V5.00 through V5.38, USG FLEX 50(W) series firmware versions V5.10 through V5.38, and USG20(W)-VPN series firmware versions V5.10 through V5.38 could allow an attacker to download or upload files via a crafted URL.

CISA’s summary

Multiple Zyxel firewalls contain a path traversal vulnerability in the web management interface that could allow an attacker to download or upload files via a crafted URL.

Weakness type: CWE-22.

Product: Zyxel Multiple Firewalls · Assigned by: Zyxel · Published: 2024-11-27

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: added 2024-12-03; federal due date 2024-12-24. Known ransomware use: Known.
• CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
• CISA SSVC assessment: exploitation active, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 2.93% probability of exploitation activity in the next 30 days; percentile 87.

Timeline

• 2024-11-27 — CVE record published by Zyxel
• 2024-12-03 — Added to CISA’s Known Exploited Vulnerabilities catalog
• 2024-12-24 — CISA remediation deadline for US federal agencies
• 2026-08-05 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. zyxel.com zyxel.com
2. Listed in CISA KEV notes (zyxel.com) zyxel.com

Vulnerability records

1. CVE.org record CVE-2024-11667 cve.org
2. NVD entry CVE-2024-11667 nvd.nist.gov

Government

1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

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