SIMATIC Drive Controller CPU 1504D TF: Improper Neutralization of Directives in Dynamically Evaluated Code
CVE-2025-40943 is a critical-severity improper neutralization of directives in dynamically evaluated code vulnerability in SIMATIC Drive Controller CPU 1504D TF from Siemens, with a CVSS 3.1 base score of 9.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version V3.1.6 as the first without the flaw, so updating SIMATIC Drive Controller CPU 1504D TF to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update SIMATIC Drive Controller CPU 1504D TF to V3.1.6 or a later version.
- Update SIMATIC Drive Controller CPU 1507D TF to V3.1.6 or a later version.
- Update SIMATIC ET 200SP CPU 1510SP F-1 PN to V2.9.9 or V4.1.2, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. 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
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- 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:N/UI:R/S:C/C:H/I:H/A:H. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.4 | Critical | CNA (siemens.com) |
| CVSS 3.1 | 9.6 | Critical | CNA (siemens.com) |
Official description
Affected devices do not properly sanitize contents of trace files. This could allow an attacker to inject code through social engineering an authorized user, who has the function right "Read diagnostics", to import a specially crafted trace file. The malicious trace file is insufficiently sanitized and malicious code could be executed in the clients browser session and trigger PLC operations via the webserver that the legitimate user is authorized to perform.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Directives in Dynamically Evaluated Code
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes code syntax before using the input in a dynamic evaluation call (e.g. eval).
How developers prevent this class of flaw
- If possible, refactor your code so that it does not need to use eval() at all.
- For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures, so the python documentation discourages use of ast.literal_eval() on untrusted data.
More Improper Neutralization of Directives in Dynamically Evaluated Code vulnerabilities (CWE-95)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in SIMATIC Drive Controller CPU 1504D TF
- 9.6 Critical severity
- 9.6 Critical severity
- 9.6 Critical severity
- 7.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
Recent Improper Neutralization of Directives in Dynamically Evaluated Code vulnerabilities
- 8.1 High severity
- 9.8 Critical severity
- 9.1 Critical severity
- 9.9 Critical severity
- 9.8 Critical severity
- 9.9 Critical severity
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