Development System 3: Allocation of Resources Without Limits or Throttling
CVE-2026-76992 is a high-severity allocation of resources without limits or throttling vulnerability in Development System 3 from Codesys, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 3.5.22.40 as the first without the flaw, so updating Development System 3 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.33% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Development System 3 to 3.5.22.40 or a later version.
- Update Gateway to 3.5.22.40 or a later version.
- Update Edge Gateway for Windows to 3.5.22.40 or a later version.
- 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 |
|---|---|---|---|
| CODESYS | Development System 3 | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Gateway | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Edge Gateway for Windows | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | HMI (SL) | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | OPC DA Server SL | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | PLCHandler | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Runtime Toolkit | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Edge Gateway for Linux | 3.15.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
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
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (cert.vde.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (cert.vde.com) |
| CVSS 3.1 | 7.5 | High | CNA (cert.vde.com) |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Allocation of Resources Without Limits or Throttling
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.
How developers prevent this class of flaw
- Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
- Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Allocation of Resources Without Limits or Throttling vulnerabilities (CWE-770)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
References
Other references
Other vulnerabilities in Development System 3
- 8.1 High severity
Recent Allocation of Resources Without Limits or Throttling vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
- 7.5 High severity
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