CVE-2021-27665Public exploitNetwork attack vector

Unauthenticated server crash via wrapped message lengths

Published Oct 11, 2021 · Updated Sep 17, 2024

Integer overflow in Johnson Controls exacqVision Web Service 21.06.11.0 and earlier allows remote attackers to crash its 32-bit Server component. The streampi.dll parser adds attacker-controlled public-key and username lengths in 32-bit arithmetic, allowing a wrapped sum to pass the type 0x205 message-length check before an oversized copy reads beyond the received buffer. The vulnerable code is in the 32-bit Server, so a standalone Web Service without that bundled component has no demonstrated exposure.

CVSS severity7.5
High
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in Johnson Controls exacqVision Web Service 21.06.11.0 and earlier allows remote attackers to crash its 32-bit Server component. The streampi.dll parser adds attacker-controlled public-key and username lengths in 32-bit arithmetic, allowing a wrapped sum to pass the type 0x205 message-length check before an oversized copy reads beyond the received buffer. The vulnerable code is in the 32-bit Server, so a standalone Web Service without that bundled component has no demonstrated exposure.

The record

CVE
CVE-2021-27665
Published
Oct 11, 2021
Updated
Sep 17, 2024
Vendor
Johnson Controls
Product
exacqVision Web Service
Classifications
CWE-190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=21.06.11.0 <=21.06.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Johnson Controls · exacqVision Web Serviceversion=21.06.11.0 <=21.06.11.0

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5Johnson ControlsCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499.004Application or System Exploitation

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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