NX: Stack-based Buffer Overflow
CVE-2026-22923 is a high-severity stack-based buffer overflow vulnerability in NX from Siemens, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version V2512 as the first without the flaw, so updating NX to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.15% 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 NX to V2512 or a later version.
- Update NX (Managed Mode) to V2512 or a later version.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
- 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | NX | before V2512 | V2512 |
| Siemens | NX (Managed Mode) | before V2512 | V2512 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- 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
- UnchangedImpact stays within the vulnerable component.
- 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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (siemens.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.3 | High | CNA (siemens.com) |
| CVSS 3.1 | 7.8 | High | CNA (siemens.com) |
Official description
A vulnerability has been identified in NX (All versions < V2512), NX (Managed Mode) (All versions < V2512). The affected application contains a data validation vulnerability that could allow an attacker with local access to interfere with internal data during the PDF export process that could potentially lead to arbitrary code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Stack-based Buffer Overflow
The product writes past the end of a buffer that was allocated on the stack.
How developers prevent this class of flaw
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implement and perform bounds checking on input.
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 vulnerabilities in NX
- 7.8 High severity
- 9.0 Critical severity
- 10.0 Critical severity
Apache Log4j2 Remote Code Execution Exploited
Recent Stack-based Buffer Overflow vulnerabilities
- 7.3 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.4 High severity
- 7.8 High severity
- 9.8 Critical severity
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