CVE-2024-40891: Zyxel DSL CPE OS Command Injection Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 11 Feb 2025, 7 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 22.9%
EPSS score, percentile 97.7 of all scored records
- How severe?
- 8.8 High
CVSS v3.1 base score, given by the CNA
- What should I do?
Required action (CISA), due 4 Mar 2025: The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization if a current mitigation is unavailable.
- Which versions are affected?
Affected: <= 1.00(AAFR.4)C0_20170615
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization if a current mitigation is unavailable.
CISA due date for this action: 4 March 2025.
Advisories and patches
Linked from CISA's catalog entry
- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-command-injection-and-insecure-default-credentials-vulnerabilities-in-certain-legacy-dsl-cpe-02-04-2025
- https://www.zyxel.com/service-provider/global/en/security-advisories/zyxel-security-advisory-command-injection-insecure-in-certain-legacy-dsl-cpe-02-04-2025
- https://nvd.nist.gov/vuln/detail/CVE-2024-40891
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | <= 1.00(AAFR.4)C0_20170615 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Multiple Zyxel DSL CPE devices contain a post-authentication command injection vulnerability in the management commands that could allow an authenticated attacker to execute OS commands via Telnet.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2024-40891 to its Known Exploited Vulnerabilities (KEV) catalog on 11 Feb 2025.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 4 Mar 2025.
- The CVE record was published on 4 Feb 2025, 7 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 8.8 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 22.9% (percentile 97.7), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
**UNSUPPORTED WHEN ASSIGNED** A post-authentication command injection vulnerability in the management commands of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C0_20170615 could allow an authenticated attacker to execute operating system (OS) commands on an affected device via Telnet.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 4 Feb 2025 | CVE record published |
| 11 Feb 2025 | Added to CISA KEV |
| 4 Mar 2025 | CISA due date for the required action |
| 21 Oct 2025 | CVE record last updated |
More exploited Zyxel vulnerabilities
- CVE-2026-7273: Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
- CVE-2024-40890: Zyxel DSL CPE OS Command Injection Vulnerability
- CVE-2024-11667: Zyxel Multiple Firewalls Path Traversal Vulnerability
- CVE-2017-6884: Zyxel EMG2926 Routers Command Injection Vulnerability
- CVE-2017-18368: Zyxel P660HN-T1A Routers Command Injection Vulnerability
- CVE-2023-27992: Zyxel Multiple NAS Devices Command Injection Vulnerability