Apache NiFi: Deserialization of Untrusted Data
CVE-2025-66524 is a high-severity deserialization of untrusted data vulnerability in Apache NiFi from Apache, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Apache NiFi versions: 1.20.0 through 2.6.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.59% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Nifi to 2.7.0 or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache NiFi | 1.20.0 through 2.6.0 | Not stated |
| Apache | Nifi | 1.20.0 up to, but not including, 2.7.0; 2.7.0 | 2.7.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.5 | High | CNA (apache.org) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
Apache NiFi 1.20.0 through 2.6.0 include the GetAsanaObject Processor, which requires integration with a configurable Distribute Map Cache Client Service for storing and retrieving state information. The GetAsanaObject Processor used generic Java Object serialization and deserialization without filtering. Unfiltered Java object deserialization does not provide protection against crafted state information stored in the cache server configured for GetAsanaObject. Exploitation requires an Apache NiFi system running with the GetAsanaObject Processor, and direct access to the configured cache server. Upgrading to Apache NiFi 2.7.0 is the recommended mitigation, which replaces Java Object serialization with JSON serialization. Removing the GetAsanaObject Processor located in the nifi-asana-processors-nar bundle also prevents exploitation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- lists.apache.org/thread/k9h004ydjg7opdvxr0nfywtzf33z60d7Issue Tracking, Mailing List
Other references
- openwall.com/lists/oss-security/2025/12/18/2Mailing List
Other vulnerabilities in Apache NiFi
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 7.2 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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