CVE-2026-102509: Apache PLC4X · Excessive Memory Allocation
Affects Apache PLC4XSource CVE Database V5
Mentioned vulnerabilities
Not known to be exploited · CVSS 8.7 High : upgrade to 1.0.0 soon.
Data as of 13 Nov 2026, 23:53 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 30 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade Apache to 1.0.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Apache Software FoundationApache PLC4X | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.plc4x:plc4j-spipkg:maven/Apache Software Foundation/org.apache.plc4x:plc4j-spiOther threats | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.plc4x:plc4j-driver-opcuapkg:maven/Apache Software Foundation/org.apache.plc4x:plc4j-driver-opcuaOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade Apache PLC4X to version 1.0.0 or later, where these issues are fixed. No other mitigations are indicated in the advisory.
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.