Exploited Ransomware

CVE-2024-11667

Zyxel Firewalls (ATP, USG FLEX, ZyWALL/USG) · Firewalls, VPNs and remote access

Zyxel Multiple Firewalls Path Traversal Vulnerability

At a glance

Exploited. Added to CISA’s catalog of exploited vulnerabilities on December 3, 2024.

Used in ransomware attacks, according to CISA.

Affected product: Zyxel Firewalls (ATP, USG FLEX, ZyWALL/USG) (category Firewalls, VPNs and remote access, indicative classification). Name in CISA’s catalog: Zyxel Multiple Firewalls.

What should I do?

Apply the patches or mitigations from Zyxel; if none are available, stop using the product.

Deadline set by CISA for US federal agencies: 21 days (due December 24, 2024). It only binds those agencies, but it is a useful measure of urgency.

Zyxel security advisories page (general page, not the advisory for this vulnerability)
The vendor’s specific advisory is listed in the NVD references: CVE-2024-11667 on the NVD website.

Original text of the required action (CISA)

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Timeline

November 27, 2024 Vulnerability published Publication date (NVD)
December 3, 2024 Exploitation confirmed Added to CISA’s KEV catalog
December 24, 2024 CISA deadline Remediation deadline set for US federal agencies

The facts, with their sources

Exploitation confirmed: Yes, on December 3, 2024 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Ransomware: Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Hunt for compromise: Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA required action: Apply the patches or mitigations from Zyxel; if none are available, stop using the product. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CISA deadline: December 24, 2024, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
Vulnerability published: November 27, 2024 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Product according to CISA: Zyxel Multiple Firewalls Filed by this site under “Firewalls, VPNs and remote access” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC

Severity and activity

9.8 / 10 CVSS severity: critical

Score from the NVD. Collected Sep 29, 2026.

— Probability of exploitation in the next 30 days (EPSS)

FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.

Description

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.

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.

Summary from CISA (KEV catalog).

CERT-FR advisories

No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.

Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.

Sources for this page

CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
NVD (NIST): CVSS severity, publication date, description, vendor references.
EPSS (FIRST): probability of exploitation.
CERT-FR: advisories and alerts (in French).
Brand and category: indicative classification by this site (method).