CVE-2026-102509
Received
Received - Intake
Memory Exhaustion in Apache PLC4X Java Implementation
Vulnerability report for CVE-2026-102509, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-30
Last updated on: 2026-09-30
Assigner: Apache Software Foundation
Description
Description
Memory Allocation with Excessive Size Value, Allocation of Resources Without Limits, and Uncontrolled Recursion in the Java implementation of Apache PLC4X (PLC4J) allow a malicious or impersonated device to exhaust the memory or stack of the client application, causing a denial of service.
In the OPC UA driver these defects are reachable before authentication: the offending data is parsed while the secure channel and session are being established, before the server's identity has been bound to it. Configuring a trusted server therefore does not prevent exploitation by an attacker who can
impersonate it.
The individual defects are:
- Length-prefixed byte strings are allocated at the size claimed on the wire before the length is checked against the data actually received (0.10.0 through 0.13.1).
- Array fields in generated protocol parsers pre-allocate a list with the element count claimed on the wire, allowing a single count field to trigger a multi-gigabyte allocation. This parser is shared by all PLC4J drivers; the OPC UA driver is the verified pre-authentication path (0.10.0 through 0.13.1).
- The OPC UA driver accumulates message chunks without enforcing the negotiated maximum chunk count and message size (0.12.0 through 0.13.1).
- The OPC UA driver pre-allocates collections using element counts received from the server (0.10.0 through 0.13.1).
- Recursive protocol types are parsed without a nesting-depth limit. The same defect in the Go implementation is covered by CVE-2026-102510 https://cveprocess.apache.org/cve5/CVE-2026-102510 .
This issue affects Apache PLC4X: from 0.10.0 before 1.0.0.
Users are recommended to upgrade to version 1.0.0, which fixes the issue.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| apache | plc4x | 1.0.0 |
| apache | plc4x | From 0.10.0 (inc) to 1.0.0 (exc) |
| apache | plc4x | From 0.10.0 (inc) to 0.13.1 (inc) |
| apache | plc4x | From 0.12.0 (inc) to 0.13.1 (inc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-674 | The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. |
| CWE-789 | The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. |
| CWE-770 | The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. |
