CVE-2025-66524: 
Java vulnerability analysis and mitigation

CVE-2025-66524 is a deserialization of untrusted data vulnerability in the Apache NiFi GetAsanaObject Processor, enabling remote code execution via crafted serialized objects injected into a configured cache server. It affects Apache NiFi versions 1.20.0 through 2.6.0 (Maven artifact org.apache.nifi:nifi-asana-processors). The vulnerability was reported on December 1, 2025, resolved on December 4, 2025, and publicly disclosed on December 18–19, 2025 by David Handermann on behalf of Apache (oss-security). The finder is credited as Jaeyeong Lee (oss-security). It carries a CVSS v3.1 base score of 8.8 (High) and a CVSS v4.0 base score of 7.5 (High) (GitHub Advisory).

The root cause is CWE-502 (Deserialization of Untrusted Data): the GetAsanaObject Processor uses generic Java Object serialization and deserialization without any filtering or allowlisting when communicating with a Distribute Map Cache Client Service (GitHub Advisory). An attacker with direct access to the configured cache server can store a crafted, malicious serialized Java object in the cache; when the GetAsanaObject Processor retrieves and deserializes this object, arbitrary code is executed in the context of the NiFi process (oss-security). Exploitation requires two preconditions: the target NiFi instance must have the GetAsanaObject Processor active, and the attacker must have direct network access to the Distribute Map Cache server. The fix in NiFi 2.7.0 replaces Java Object serialization with JSON serialization, which is not susceptible to this class of attack (GitHub Advisory). The issue is tracked upstream as NIFI-15292 (oss-security).

Successful exploitation allows an attacker to execute arbitrary code on the Apache NiFi host system, resulting in full compromise of confidentiality, integrity, and availability of the affected NiFi instance (GitHub Advisory). This could lead to data theft (including sensitive Asana workflow data and NiFi pipeline credentials), unauthorized modification of data flows, or complete service disruption. Given NiFi's role as a data integration platform, a compromised instance may also serve as a pivot point for lateral movement into connected data systems and downstream services (GitHub Advisory).

1. Reconnaissance: Identify Apache NiFi deployments running versions 1.20.0–2.6.0 with the GetAsanaObject Processor active and a Distribute Map Cache Client Service configured.
2. Gain cache server access: Obtain direct network access to the Distribute Map Cache server associated with the target NiFi instance (e.g., via network misconfiguration, compromised credentials, or insider access).
3. Craft malicious payload: Use a Java deserialization gadget chain tool (e.g., ysoserial) to generate a serialized Java object payload that executes arbitrary commands when deserialized by the NiFi JVM.
4. Inject payload into cache: Write the crafted serialized object into the Distribute Map Cache server under a key that the GetAsanaObject Processor will retrieve as state information.
5. Trigger deserialization: Wait for or trigger the GetAsanaObject Processor to poll the cache server and deserialize the malicious object, resulting in arbitrary code execution on the NiFi host (oss-security, GitHub Advisory).

• Network: Unexpected or unauthorized connections to the Distribute Map Cache server port from external or untrusted hosts; unusual outbound connections from the NiFi server to unknown IPs following cache reads.
• Logs: NiFi application logs (nifi-app.log) showing deserialization errors or unexpected class loading events originating from the GetAsanaObject Processor; Java exceptions related to unknown or unexpected serialized class types.
• Process: Unusual child processes spawned by the NiFi JVM (e.g., bash, sh, curl, wget, python) that are not part of normal NiFi operation.
• File System: Unexpected new files, scripts, or web shells written to the NiFi installation directory or temp directories by the NiFi process account.

The primary recommended mitigation is upgrading to Apache NiFi 2.7.0, which replaces unsafe Java Object serialization with JSON serialization in the GetAsanaObject Processor (GitHub Advisory). As an immediate workaround, organizations that do not require Asana integration should remove the GetAsanaObject Processor by deleting or disabling the nifi-asana-processors-nar bundle (oss-security). Additionally, network access to the Distribute Map Cache server should be restricted to only trusted NiFi hosts using firewall rules or network segmentation to reduce the attack surface even before patching.

The vulnerability was disclosed via the Apache security mailing list and oss-security by Apache NiFi committer David Handermann, crediting researcher Jaeyeong Lee as the finder (oss-security). Security news outlets such as SecurityOnline.info covered the disclosure, highlighting the risk to Asana-integrated NiFi workflows (GitHub Advisory). Community discussion was noted on Bluesky and Mastodon/Infosec.exchange, with general acknowledgment of the limited exploitability due to the required preconditions.