CVE-2021-27198Public exploitNetwork attack vector

Unauthenticated code execution via arbitrary file upload

Published Feb 26, 2021 · Updated Aug 3, 2024

Arbitrary file upload in Visualware MyConnection Server before 11.1a allows remote attackers to execute code through its web service. The unauthenticated myspeed/sf handler accepts a filename parameter and writes the POST body to an attacker-chosen filesystem location without constraining the path or file type. An attacker can place code where the Java service or an operating-system execution trigger loads it, yielding SYSTEM on Windows or root on Linux; direct JAR loading requires an active license.

CVSS severity9.8
Critical
EPSS probability13.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file upload in Visualware MyConnection Server before 11.1a allows remote attackers to execute code through its web service. The unauthenticated myspeed/sf handler accepts a filename parameter and writes the POST body to an attacker-chosen filesystem location without constraining the path or file type. An attacker can place code where the Java service or an operating-system execution trigger loads it, yielding SYSTEM on Windows or root on Linux; direct JAR loading requires an active license.

The record

CVE
CVE-2021-27198
Published
Feb 26, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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