CVE-2024-40890
HIGHCVE-2024-40890 is a high-severity (CVSS 8.8) OS Command Injection vulnerability in zyxel sbg3300-n000 firmware. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-02-11) — treat it as actively exploited and patch now. O3 Security detects and blocks CVE-2024-40890 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
**UNSUPPORTED WHEN ASSIGNED** A post-authentication command injection vulnerability in the CGI program of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C0_20170615…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2025-02-11. Federal agencies were required to remediate by 2025-03-04.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2024-40890.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2024-40890 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 368,770 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Description
UNSUPPORTED WHEN ASSIGNED A post-authentication command injection vulnerability in the CGI program 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 by sending a crafted HTTP POST request.
Affected Products
sbg3300-n000 firmwarezyxelsbg3300-nb00 firmwarezyxelsbg3500-n000 firmwarezyxelsbg3500-nb00 firmwarezyxelvmg1312-b10a firmwarezyxelvmg1312-b10b firmwarezyxelDetection & mitigation playbook
Vendor / applianceDetect
Inventory every zyxel sbg3300-n000 firmware deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2024-40890 yet — track the zyxel sbg3300-n000 firmware advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2024-40890 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2024-40890. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-40890 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2024-40890 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.