CVE-2026-102509

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 4 sources updated this week
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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 v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
54
EG Risk 54/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity87% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
31st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 30, 2026

Last Modified

September 30, 2026

Advisory Details (1)

Auto-updated Sep 30, 2026
Fix named in the CVE record.
generic

Pony Mail

https://lists.apache.org/thread.html/qngc85qhnlj7kpk3z58z0xlxhz2tn6gp

Vendor Advisories for CVE-2026-102509(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 21× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-04 01:20 UTCEG score recompute
  2. 2026-10-04 01:20 UTCGHSA enrichment
  3. 2026-10-03 14:25 UTCEPSS rescore
  4. 2026-10-03 13:47 UTCGHSA enrichment
  5. 2026-10-03 02:11 UTCEG score recompute
  6. 2026-10-03 02:11 UTCGHSA enrichment
  7. 2026-10-02 14:38 UTCGHSA enrichment
  8. 2026-10-02 03:07 UTCEG score recompute
  9. 2026-10-02 03:06 UTCGHSA enrichment
  10. 2026-10-01 19:49 UTCEPSS rescore
  11. 2026-10-01 15:33 UTCGHSA enrichment
  12. 2026-10-01 03:56 UTCGHSA enrichment
  13. 2026-09-30 16:23 UTCGHSA enrichment
  14. 2026-09-30 15:38 UTCEG score recompute
  15. 2026-09-30 15:38 UTCGHSA enrichment
  16. 2026-09-30 15:02 UTCEPSS rescore
  17. 2026-09-30 14:53 UTCEG score recompute
  18. 2026-09-30 14:53 UTCGHSA enrichment
  19. 2026-09-30 09:28 UTCEG score recompute
  20. 2026-09-30 08:30 UTCEG score recompute
  21. 2026-09-30 08:29 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-102509?
CVE-2026-102509 is a high vulnerability published on September 30, 2026. 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…
When was CVE-2026-102509 disclosed?
CVE-2026-102509 was first published on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-102509 actively exploited?
CVE-2026-102509 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102509?
CVE-2026-102509 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102509?
A fix for CVE-2026-102509 is available — its CVE record says: "Users are recommended to upgrade to version 1.0.0, which fixes the issue." The vendor advisories EchelonGraph has for CVE-2026-102509 are linked in the Vendor Advisories panel on this page.

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