CVE-2021-33023Network attack vector

Administrator code execution via IOCTL buffer overflow

Published Oct 18, 2021 · Updated Sep 17, 2024

Heap-based buffer overflow in Advantech WebAccess 9.02 and earlier allows remote attackers to execute code via crafted IOCTL data. The IOCTL 0x2722 handler copies user-supplied data into a heap buffer without validating its length. An unauthenticated network request is sufficient to execute code in the Administrator context, enabling full host compromise.

CVSS severity9.8
Critical
EPSS probability2.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Advantech WebAccess 9.02 and earlier allows remote attackers to execute code via crafted IOCTL data. The IOCTL 0x2722 handler copies user-supplied data into a heap buffer without validating its length. An unauthenticated network request is sufficient to execute code in the Administrator context, enabling full host compromise.

The record

CVE
CVE-2021-33023
Published
Oct 18, 2021
Updated
Sep 17, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-122, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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

9.8Zero Day InitiativeCVSS: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.

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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-122Heap-based Buffer Overflow
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

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Your stack

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