CVE-2021-38389Network attack vector

Administrator code execution via unchecked IOCTL length

Published Oct 18, 2021 · Updated Sep 16, 2024

Stack-based buffer overflow in Advantech WebAccess 9.02 and earlier allows remote attackers to execute code as Administrator. The handler for IOCTL 0x1138B copies user-supplied data into a fixed-length stack buffer without first validating its length. Network access to the affected service is sufficient; no authentication or user interaction is required, and successful exploitation runs code with Administrator privileges.

CVSS severity9.8
Critical
EPSS probability10.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack-based buffer overflow in Advantech WebAccess 9.02 and earlier allows remote attackers to execute code as Administrator. The handler for IOCTL 0x1138B copies user-supplied data into a fixed-length stack buffer without first validating its length. Network access to the affected service is sufficient; no authentication or user interaction is required, and successful exploitation runs code with Administrator privileges.

The record

CVE
CVE-2021-38389
Published
Oct 18, 2021
Updated
Sep 16, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-121, CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8ICS-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo