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CISA KEV · ACTIVELY EXPLOITED
HIGH severity

CVE-2018-4063

HIGH

CVE-2018-4063 is a high-severity (CVSS 8.8) Unrestricted File Upload vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2025-12-12) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

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,…

Published
Updated
Affected
1 product
Patched
See advisory
Exploits
1 known
Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2025-12-12. Federal agencies were required to remediate by 2026-01-02.
  • 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-2018-4063.

EPSS Exploitation Probability

via FIRST.org ↗
27.3%probability of exploitation in next 30 days
Moderate Risk+0.20%
Lower risk than most CVEs98th percentile — riskier than 98% of all scored CVEsHighest risk
26.6%27.2%27.9%28.6%28.1%27.1%27.1%27.3%Jul 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2018-4063 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.

Description

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.

Affected Products

1 product · 3 configurations
OS
aleossierrawireless
< 4.9.4
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An exploitable remote code execution vulnerability exists in the upload.…

talosintelligence.comNVDMay 2019

Detection & mitigation playbook

Vulnerability

  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2018-4063 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.

Frequently Asked Questions

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.
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CVE-2018-4063: Unrestricted File Upload (High 8.8, KEV)