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HIGH · CVSS 8.8 CISA Known Exploited Vulnerability

CVE-2018-4063

Sierra Wireless AirLink ALEOS Unrestricted Upload of File with Dangerous Type Vulnerability

Sierra Wireless AirLink ALEOS

An exploitable remote code execution vulnerability exists in the upload.cgi functionality of Sierra Wireless AirLink ES450 FW 4.9.3. A specially crafted HTTP request can upload a file, resulting in executable code being uploaded, and routable, to the webserver. An attacker can make an authenticated HTTP request to trigger this vulnerability.

CVSS
8.8
HIGH
EPSS
27.3%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
6 May 2019
CWE-434

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 12 December 2025. US federal agencies were required to remediate it by 2 January 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 27.3%, which is higher than 98.1% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2018-4063 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2018-4063.

What does CVE-2018-4063 affect?

CVE-2018-4063 affects Sierra Wireless AirLink ALEOS. An exploitable remote code execution vulnerability exists in the upload.cgi functionality of Sierra Wireless AirLink ES450 FW 4.9.3. A specially crafted HTTP request can upload a file, resulting in executable code being uploaded, and routable, to the webserver. An attacker can make an authenticated HTTP request to trigger this vulnerability.

How severe is CVE-2018-4063?

CVE-2018-4063 is rated HIGH with a CVSS base score of 8.8. EPSS puts the probability of exploitation in the next 30 days at 27.3%, higher than 98.1% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 2 January 2026.

How should organisations respond to CVE-2018-4063?

Apply the vendor patch for Sierra Wireless AirLink ALEOS as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.