Apache Axis2/Java: Deserialization of Untrusted Data
CVE-2026-66713 is a critical-severity deserialization of untrusted data vulnerability in Apache Axis2/Java from Apache, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Axis2/Java versions: 2.0.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.72% chance of exploitation within 30 days, higher than 78% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Axis2/java to 2.0.1 or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Axis2/Java | 2.0.0 and earlier | Not stated |
| Apache | Axis2/java | before 2.0.1 | 2.0.1 |
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
- NoneNo account or login is needed.
- 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:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Deserialization of Untrusted Data (CWE-502) in the Tribes-based clustering component in Apache Software Foundation Apache Axis2/Java through 2.0.0 on Apache Tomcat (only when Tribes clustering is enabled, which is off by default) allows an unauthenticated remote attacker with network access to the clustering port to execute arbitrary code via a crafted serialized Java object delivered to the cluster channel and deserialized in org.apache.axis2.clustering.tribes.Axis2ChannelListener#messageReceived. Users are recommended to upgrade to version 2.0.1, which fixes this issue by removing the clustering feature entirely.
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: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Third-party and government advisories
- openwall.com/lists/oss-security/2026/07/28/2Mailing List, Third Party Advisory
Other vulnerabilities in Apache Axis2/Java
- 7.5 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.5 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 10.0 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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