On July 30, 2026, ABB published cyber security advisory 9AKK108472A9037 disclosing that ABB Ability zenon installations which include IIoT Services ship with MongoDB version 4.2 as the engine behind the MongoDB-based Persistence Service. MongoDB 4.2 reached end-of-life status and no longer receives security updates or patches from its vendor, leaving the bundled component exposed to thirteen publicly disclosed vulnerabilities that will never be remediated upstream. Five of the thirteen carry high severity ratings and eight are rated medium. Only zenon deployments where IIoT Services are installed and in use are affected; systems without IIoT Services do not carry the MongoDB dependency and are outside the scope of this advisory.
The most consequential of the thirteen is CVE-2025-14847, publicly tracked as MongoBleed, which carries a CVSS v3.1 base score of 7.5 and a CVSS v4.0 score of 8.7. Mismatched length fields in zlib-compressed protocol headers allow an unauthenticated client to read uninitialized heap memory from the database process. Because message decompression occurs before authentication is performed, any client able to reach the MongoDB listener over the network can trigger the flaw without credentials, and the disclosed memory may contain credentials, session tokens, API keys, or historized process values held in adjacent allocations. The remaining twelve vulnerabilities cluster around denial of service, authorization bypass, certificate validation failures, log integrity, and local privilege escalation in MongoDB tooling.
The risk context is materially elevated by exploitation status. The U.S. Cybersecurity and Infrastructure Security Agency added CVE-2025-14847 to its Known Exploited Vulnerabilities catalog on December 29, 2025, confirming exploitation in the wild, and public proof-of-concept exploit code is available. ABB states that it had received no reports of exploitation targeting zenon specifically at the time the advisory was issued, and that zenon's bundling of the vulnerable MongoDB version was identified during internal assessment rather than through public disclosure. That distinction offers limited comfort: opportunistic scanning for exposed MongoDB listeners does not distinguish between a general-purpose database and one embedded inside a supervisory control platform. zenon is widely deployed as an HMI and SCADA layer across energy, water, food and beverage, pharmaceutical, and automotive operations, which places the affected component inside process control environments where availability loss carries physical consequence.
CVE-2025-14847, with a CVSS v3.1 score of 7.5 and a CVSS v4.0 score of 8.7, is an improper handling of length parameter inconsistency flaw (CWE-130) in MongoDB's zlib-compressed wire protocol path. The compressed message header declares the expected size of the uncompressed payload, and the affected decompression logic returned the size of the allocated output buffer rather than the length of the data actually decompressed. An undersized or deliberately malformed compressed payload therefore causes the server to return adjacent uninitialized heap memory to the requesting client. The flaw affects MongoDB Server 4.2 releases at or above 4.2.0 with no fixed release available in that branch, alongside supported branches fixed in 7.0.28, 8.0.17, 8.2.3, 6.0.27, 5.0.32, and 4.4.30. Because the vulnerable code path executes prior to authentication, exploitation requires only network reachability to the database port, and repeated requests allow an attacker to harvest memory contents incrementally until sensitive material surfaces.
CVE-2020-7928, with a CVSS v3.1 score of 6.5, is an improper neutralization of null byte weakness (CWE-158) that allows a user authorized to perform database queries to trigger a read overrun and access arbitrary memory through specially crafted queries. The issue affects MongoDB Server 4.2 versions prior to 4.2.9, along with 4.4 versions prior to 4.4.1, 4.0 versions prior to 4.0.20, and 3.6 versions prior to 3.6.20. In a zenon IIoT Services deployment, the credentials required for this attack are those held by the Persistence Service itself or by any account provisioned for integration and reporting access, which makes the prerequisite considerably weaker in practice than the authenticated rating suggests.
Six of the thirteen vulnerabilities produce denial of service against the database process, and their combined effect is the loss of the historization and data-integration functions that IIoT Services provides. CVE-2020-7925, with a CVSS v3.1 score of 7.5, allows an unauthenticated attacker to exploit incorrect validation in the role name parser (CWE-475) and crash the server using a specially crafted request, affecting 4.2 versions prior to 4.2.9. CVE-2021-32040, also scored 7.5, permits an extremely long aggregation pipeline to overflow the stack and crash mongod under default configuration (CWE-787 and CWE-121), affecting 4.2 versions up to and including 4.2.16. CVE-2021-32036, scored 7.1, allows an authenticated user with no specific authorizations to repeatedly invoke the features command until resource depletion or lock contention degrades service and, in rare cases, corrupts id field values (CWE-770). CVE-2020-7929 and CVE-2020-7923, each scored 6.5, allow an authorized user to crash the server through specially crafted regular expression queries (CWE-185) and geoNear queries that violate a query subsystem invariant (CWE-248) respectively. CVE-2021-20330, scored 6.5, allows an attacker holding basic CRUD permissions on a replicated collection to run applyOps with malformed oplog entries and crash replica set secondaries (CWE-617), affecting 4.2 versions prior to 4.2.16.
CVE-2021-20328, with a CVSS v3.1 score of 6.8, and CVE-2020-7924, with a CVSS v3.1 score of 6.5, both concern improper certificate validation (CWE-295) and together undermine the transport protections that operators typically rely on to compensate for an unpatchable component. In the first, MongoDB Java driver versions supporting client-side field level encryption fail to verify the host name on the Key Management Service server certificate, allowing an attacker in a privileged network position to intercept driver-to-KMS traffic and render field level encryption ineffective. In the second, a command line parameter in MongoDB Database Tools intended only to skip host name checks causes the tools to skip certificate validation entirely, so backup, restore, and export operations may proceed against an attacker-controlled endpoint presenting an invalid certificate.
CVE-2020-7921, with a CVSS v3.1 score of 5.3, is an incorrect authorization weakness (CWE-863) in which improper serialization of internal state in the authorization subsystem permits a user holding valid credentials to bypass per-user IP whitelisting following an administrative action. The issue affects MongoDB Server 4.2 versions prior to 4.2.3 alongside 4.0, 4.3, and 3.6 branches. Where an operator has restricted database access to a defined set of engineering workstations or historian collectors, this flaw silently removes that restriction after routine administration, converting a network-scoped control into a credential-only control without any indication to the administrator that enforcement has lapsed.
The final two vulnerabilities affect evidentiary integrity and endpoint privilege boundaries rather than the database service itself. CVE-2021-20333, with a CVSS v3.1 score of 5.3, allows specially crafted commands to inject newline characters into MongoDB server log entries (CWE-116 and CWE-117), generating artificial log records or splitting genuine ones, which degrades the reliability of the database logs an investigator would use to reconstruct activity after an incident. CVE-2021-20334, with a CVSS v3.1 score of 7.8, is a local privilege escalation in MongoDB Compass for Windows (CWE-250) in which a third party with local access to the machine can execute arbitrary software with the privileges of the user running Compass, affecting Compass 1.x version 1.3.0 and later versions prior to 1.25.0. On an engineering workstation where an operator holds elevated rights to the zenon environment, that escalation path reaches directly into the control system.
Operationally, the exposure is concentrated in the data historization and integration tier rather than in real-time supervisory control, but the distinction is narrower than it appears. IIoT Services collect, process, and integrate industrial data across multiple systems and are frequently deployed on separate machines or in cloud-connected topologies using web-based access, which means the affected MongoDB instance often sits at a boundary between the process network and enterprise or vendor-facing networks. A successful denial of service against the Persistence Service interrupts historization, breaks reporting and analytics feeds, and removes the data record that operations and engineering staff depend on for trend analysis and post-event review, while the unauthenticated memory disclosure in MongoBleed offers a path to credential material that can be reused to move further into the control environment. Because MongoDB 4.2 is end-of-life, no patch will arrive for the 4.2 branch, so remediation requires architectural change rather than update deployment.
From a compliance standpoint, running an end-of-life database component inside a supervisory control platform is difficult to defend under any of the frameworks that govern industrial operators. NERC CIP-007 requires a documented patch management process with evaluation and remediation of applicable security patches, and a component that structurally cannot receive patches forces the operator into a formally documented mitigation plan with compensating controls rather than a routine patch cycle. IEC 62443-2-3 and IEC 62443-3-3 similarly expect a maintained software inventory and controlled patch state for components in a defined security zone. The presence of a KEV-listed, actively exploited vulnerability raises the stakes further for U.S. federal civilian agencies and their contractors subject to CISA Binding Operational Directive 22-01, and for regulated water, energy, and pharmaceutical operators the combination of unpatchable software and a documented remote data-disclosure path is likely to attract auditor attention. Organizations subject to breach notification regimes should also note that the memory disclosed by MongoBleed may include process data or personal data held in adjacent allocations, which affects the assessment obligation following any confirmed exploitation.
ABB has published mitigation guidance for this advisory, and because no patch exists for the end-of-life MongoDB 4.2 branch, remediation depends on removing or replacing the vulnerable component rather than updating it. The following actions are recommended in priority order:
Beyond these product-specific steps, ABB recommends established system protection measures including segregation of untrusted networks from automation networks, removal of unnecessary communication links and unused services, application of least-privilege role-based access, maintenance of validated backups, and periodic assessment and patching of the wider system.
1898 & Co. has extensive experience supporting operational technology security programs across electric, water, oil and gas, and manufacturing environments, including asset owners running zenon and comparable HMI and SCADA platforms. Our teams help clients build and maintain accurate software inventories for control system assets, which is the foundation for identifying embedded end-of-life components such as the MongoDB instance described in this advisory. Where a vulnerable component cannot be patched, we work alongside client engineering and operations staff to design compensating controls that reduce exposure without disrupting production.
Our OT security assessment services examine network segmentation, remote access paths, and data historization architecture to identify where components like IIoT Services bridge process and enterprise networks. We help clients validate that firewall rules, zone boundaries, and demilitarized zone designs actually constrain reachability to database and integration services as intended, and we document the compensating control set in a form suitable for NERC CIP and IEC 62443 evidence packages. For organizations operating under a formally documented mitigation plan because a component cannot be patched, we assist in developing the technical justification and the ongoing verification activity that regulators expect to accompany it.
1898 & Co. also operates a managed threat detection and response capability purpose-built for industrial environments, with analysts who understand control system protocols and operational context. That capability supports hunting for the specific behaviors associated with this advisory, including anomalous access to MongoDB listeners, malformed compressed protocol traffic, and unexplained database service restarts. Clients seeking assistance in scoping their zenon exposure, executing the removal or replacement of the bundled MongoDB component, or establishing detection coverage for exploitation attempts can engage our OT cybersecurity team for support.