Uncontrolled Memory Allocation in CODESYS Gateway Client (CVE-2026-76992) | HOL Guard CVE

High · CVSS 8.7CVE-2026-76992

Uncontrolled Memory Allocation in CODESYS Gateway Client

Answer in brief

CVE-2026-76992 records a High severity (CVSS 8.7) vulnerability in Uncontrolled Memory Allocation in CODESYS Gateway Client. The current sources do not mark it as known exploited. The current feed maps CODESYS/Development System 3 (generic), CODESYS/Edge Gateway for Linux (generic), CODESYS/Edge Gateway for Windows (generic), CODESYS/Gateway (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 30, 2026Updated Sep 30, 2026Source checked Sep 30, 2026First seen by HOL Sep 30, 2026Material review Sep 30, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 8 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps CODESYS/Development System 3 (generic), CODESYS/Edge Gateway for Linux (generic), CODESYS/Edge Gateway for Windows (generic), CODESYS/Gateway (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
CODESYS/Development System 3generic	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/Edge Gateway for Linuxgeneric	>=3.15.0.0 <4.23.0.0	4.23.0.0
CODESYS/Edge Gateway for Windowsgeneric	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/Gatewaygeneric	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/HMI (SL)generic	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/OPC DA Server SLgeneric	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/PLCHandlergeneric	>=3.0.0.0 <3.5.22.40	3.5.22.40
CODESYS/Runtime Toolkitgeneric	>=3.0.0.0 <3.5.22.40	3.5.22.40

Recommended response

Check inventory. Check lockfiles and deployed manifests for CODESYS/Development System 3, CODESYS/Edge Gateway for Linux, CODESYS/Edge Gateway for Windows.
Review the reported fix. Update CODESYS/Development System 3 to 3.5.22.40; CODESYS/Edge Gateway for Linux to 4.23.0.0; CODESYS/Edge Gateway for Windows to 3.5.22.40; CODESYS/Gateway to 3.5.22.40; CODESYS/HMI (SL) to 3.5.22.40; CODESYS/OPC DA Server SL to 3.5.22.40; CODESYS/PLCHandler to 3.5.22.40; CODESYS/Runtime Toolkit to 3.5.22.40 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 30, 2026

Sources and claim methodology

Source referencecertvde.com

Upstream source description

The CODESYS Gateway Client allocates memory based on a size field in a gateway response without enforcing an appropriate upper limit. An unauthenticated remote attacker controlling a malicious gateway can exploit this behavior to trigger excessive memory consumption, resulting in a denial-of-service condition thus leading to a total loss of availablity.

Quoted source text, attributed separately from HOL analysis.