ICSA-26-125-05

Vulnerability from csaf_cisa - Published: 2026-05-05 06:00 - Updated: 2026-05-05 06:00
Summary
Johnson Controls CEM AC2000
Notes
Legal Notice and Terms of Use: This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Advisory Summary: Successful exploitation of this vulnerability could allow a standard user to escalate privileges on the host machine.
Critical infrastructure sectors: Critical Manufacturing, Commercial Facilities, Government Services and Facilities, Transportation Systems, Energy
Countries/areas deployed: Worldwide
Company headquarters location: Ireland
Recommended Practices: CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
Recommended Practices: Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
Recommended Practices: Locate control system networks and remote devices behind firewalls and isolating them from business networks.
Recommended Practices: When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
Recommended Practices: CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Recommended Practices: CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Recommended Practices: CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Recommended Practices: Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Recommended Practices: Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
Recommended Practices: CISA also recommends users take the following measures to protect themselves from social engineering attacks:
Recommended Practices: Do not click web links or open attachments in unsolicited email messages.
Recommended Practices: Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
Recommended Practices: Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.
Recommended Practices: No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.
CVE-2026-21661
8.7 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
CWE-427 - Uncontrolled Search Path Element
Mitigation Johnson Controls recommends users apply the following mitigations:
Mitigation Upgrade CEM AC 2000 12.0 to 12.0 Release 10.
Mitigation Upgrade CEM AC 2000 11.0 to 11.0 Release 9.
Mitigation Upgrade CEM AC 2000 10.6 to 10.6 Release 3.
Mitigation For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory. https://www.johnsoncontrols.com/trust-center/cybe…
References
Acknowledgments
CSACyber Tom Hulme
To clipboard 

{
  "document": {
    "acknowledgments": [
      {
        "names": [
          "Tom Hulme"
        ],
        "organization": "CSACyber",
        "summary": "reported this vulnerability to Johnson Controls"
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Disclosure is not limited",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.cisa.gov/news-events/news/traffic-light-protocol-tlp-definitions-and-usage"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy \u0026 Use policy (https://www.cisa.gov/privacy-policy).",
        "title": "Legal Notice and Terms of Use"
      },
      {
        "category": "summary",
        "text": "Successful exploitation of this vulnerability could allow a standard user to escalate privileges on the host machine.",
        "title": "Advisory Summary"
      },
      {
        "category": "other",
        "text": "Critical Manufacturing, Commercial Facilities, Government Services and Facilities, Transportation Systems, Energy",
        "title": "Critical infrastructure sectors"
      },
      {
        "category": "other",
        "text": "Worldwide",
        "title": "Countries/areas deployed"
      },
      {
        "category": "other",
        "text": "Ireland",
        "title": "Company headquarters location"
      },
      {
        "category": "general",
        "text": "CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Locate control system networks and remote devices behind firewalls and isolating them from business networks.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA also recommends users take the following measures to protect themselves from social engineering attacks:",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Do not click web links or open attachments in unsolicited email messages.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.",
        "title": "Recommended Practices"
      }
    ],
    "publisher": {
      "category": "coordinator",
      "contact_details": "central@cisa.dhs.gov",
      "name": "CISA",
      "namespace": "https://www.cisa.gov/"
    },
    "references": [
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-26-125-05 JSON",
        "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-125-05.json"
      },
      {
        "category": "self",
        "summary": "ICSA Advisory ICSA-26-125-05 - Web Version",
        "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-125-05"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/resources-tools/resources/ics-recommended-practices"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/sites/default/files/publications/Cybersecurity_Best_Practices_for_Industrial_Control_Systems.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/topics/industrial-control-systems"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/sites/default/files/publications/emailscams0905.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/ncas/tips/ST04-014"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/news-events/news/targeted-cyber-intrusion-detection-and-mitigation-strategies-update-b"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/secure-our-world/teach-employees-avoid-phishing"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/news-events/news/avoiding-social-engineering-and-phishing-attacks"
      }
    ],
    "title": "Johnson Controls CEM AC2000",
    "tracking": {
      "current_release_date": "2026-05-05T06:00:00.000000Z",
      "generator": {
        "date": "2026-05-04T19:43:52.613666Z",
        "engine": {
          "name": "CISA CSAF Generator",
          "version": "1.0.0"
        }
      },
      "id": "ICSA-26-125-05",
      "initial_release_date": "2026-05-05T06:00:00.000000Z",
      "revision_history": [
        {
          "date": "2026-05-05T06:00:00.000000Z",
          "legacy_version": "Initial",
          "number": "1",
          "summary": "Initial Republication of Johnson Controls product security advisory."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "12.0",
                "product": {
                  "name": "Johnson Controls Inc. CEM AC2000: 12.0",
                  "product_id": "CSAFPID-0001"
                }
              }
            ],
            "category": "product_name",
            "name": "CEM AC2000"
          },
          {
            "branches": [
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                }
              }
            ],
            "category": "product_name",
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          {
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                "name": "10.6",
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                  "product_id": "CSAFPID-0003"
                }
              }
            ],
            "category": "product_name",
            "name": "CEM AC2000"
          }
        ],
        "category": "vendor",
        "name": "Johnson Controls Inc."
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-21661",
      "cwe": {
        "id": "CWE-427",
        "name": "Uncontrolled Search Path Element"
      },
      "notes": [
        {
          "category": "summary",
          "text": "The affected product is vulnerable to DLL hijacking, which could allow an attacker to escalate standard user privileges on the host machine.",
          "title": "Vulnerability Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-0001",
          "CSAFPID-0002",
          "CSAFPID-0003"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "cwe.mitre.org",
          "url": "https://cwe.mitre.org/data/definitions/427.html"
        },
        {
          "category": "external",
          "summary": "www.cve.org",
          "url": "https://www.cve.org/CVERecord?id=CVE-2026-21661"
        },
        {
          "category": "external",
          "summary": "www.first.org",
          "url": "https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L"
        },
        {
          "category": "external",
          "summary": "www.first.org",
          "url": "https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "remediations": [
        {
          "category": "mitigation",
          "details": "Johnson Controls recommends users apply the following mitigations:",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "Upgrade CEM AC 2000 12.0 to 12.0 Release 10.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "Upgrade CEM AC 2000 11.0 to 11.0 Release 9.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "Upgrade CEM AC 2000 10.6 to 10.6 Release 3.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ],
          "url": "https://www.johnsoncontrols.com/trust-center/cybersecurity/security-advisories"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        }
      ]
    }
  ]
}


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Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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