Control RTE (SL): Concurrent Execution using Shared Resource with Improper Synchronization
CVE-2026-79625 is a high-severity concurrent execution using shared resource with improper synchronization vulnerability in Control RTE (SL) from Codesys, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 3.5.22.40 as the first without the flaw, so updating Control RTE (SL) to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.23% 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 Control RTE (SL) to 3.5.22.40 or a later version.
- Update Control RTE (for Beckhoff CX) SL to 3.5.22.40 or a later version.
- Update Control Win (SL) to 3.5.22.40 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| CODESYS | Control RTE (SL) | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Control RTE (for Beckhoff CX) SL | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Control Win (SL) | 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 | Safety SIL2 | 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 | Development System 3 | 3.0.0.0 up to, but not including, 3.5.22.40 | 3.5.22.40 |
| CODESYS | Control for BeagleBone SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for emPC-A/iMX6 SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for IOT2000 SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for Linux ARM SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for Linux SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for PFC100 SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for PFC200 SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for PLCnext SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for Raspberry Pi SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Control for WAGO Touch Panels 600 SL | 3.5.0.0 up to, but not including, 4.23.0.0 | 4.23.0.0 |
| CODESYS | Virtual Control SL | 3.5.0.0 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. Scored by CNA (cert.vde.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.2 | High | CNA (cert.vde.com) |
| CVSS 3.1 | 8.1 | High | CNA (cert.vde.com) |
Official description
Affected products do not properly synchronize access to their monitoring functionality. When multiple clients send concurrent requests, this may lead to incorrect reads or writes, or to corruption of internal memory structures. An authenticated remote attacker with monitoring access can exploit this issue to cause incorrect data processing or a denial-of-service condition.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Concurrent Execution using Shared Resource with Improper Synchronization
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
How developers prevent this class of flaw
- In languages that support it, use synchronization primitives. Only wrap these around critical code to minimize the impact on performance.
- Use thread-safe capabilities such as the data access abstraction in Spring.
- Minimize the usage of shared resources in order to remove as much complexity as possible from the control flow and to reduce the likelihood of unexpected conditions occurring. Additionally, this will minimize the amount of synchronization necessary and may even help to reduce the likelihood of a denial of service where an attacker may be able to repeatedly trigger a critical section (CWE-400).
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
References
Other references
Other vulnerabilities in Control RTE (SL)
- 7.5 High severity
- 7.5 High severity
- 8.3 High severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
Recent Concurrent Execution using Shared Resource with Improper Synchronization vulnerabilities
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- 7.0 High severity
- 8.1 High severity
- 7.1 High severity
- 8.8 High severity
- 7.8 High severity
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