CVE-2026-25644 is a vulnerability identified in the DataHub open-source metadata platform, specifically affecting the LDAP ingestion source component in versions prior to 1.3.1.8. The root cause is improper certificate validation (CWE-295), which allows an attacker to perform a TLS downgrade attack. In this scenario, an attacker positioned between the client and server can force the communication to use a weaker or no encryption protocol, bypassing the intended TLS protections. This vulnerability does not require any privileges or user interaction, making it remotely exploitable over the network. The impact is primarily on confidentiality, as an attacker can intercept sensitive metadata being ingested via LDAP, potentially exposing organizational data lineage, schema, and other metadata critical for data governance. The vulnerability has a CVSS v3.1 base score of 7.5, reflecting its high severity due to network attack vector, no required privileges, and no user interaction. The issue was addressed and patched in DataHub version 1.3.1.8 by enforcing proper certificate validation and preventing TLS downgrade attempts. No public exploits have been reported yet, but the vulnerability's nature makes it a significant risk for organizations relying on DataHub for metadata management.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive metadata, which may include data lineage, classification, and access policies. Such exposure can undermine data governance, compliance efforts (e.g., GDPR), and intellectual property protection. Attackers exploiting this flaw could gain insights into organizational data structures, potentially aiding further attacks or data exfiltration. Since the vulnerability allows MITM attacks without authentication, any organization using vulnerable DataHub versions on networks accessible to attackers (including internal networks with insufficient segmentation) is at risk. This is particularly critical for sectors with stringent data privacy requirements such as finance, healthcare, and government. The confidentiality breach could also damage trust and lead to regulatory penalties. Availability and integrity are not directly impacted, but the confidentiality loss alone justifies urgent remediation.

The primary mitigation is to upgrade DataHub to version 1.3.1.8 or later, where the vulnerability is patched. Organizations should audit their DataHub deployments to identify and remediate any instances running affected versions. Network-level protections such as enforcing strict TLS configurations and disabling legacy protocols can reduce exposure. Implementing network segmentation and monitoring LDAP traffic for anomalies can help detect potential MITM attempts. Additionally, organizations should review their certificate management practices to ensure proper validation and pinning where feasible. Employing intrusion detection systems capable of identifying TLS downgrade attempts can provide early warning. Finally, educating administrators about the risks of using outdated software and enforcing timely patch management policies will reduce future vulnerabilities.