Sentinel Keys Server: Stack-based Buffer Overflow
CVE-2026-78402 is a high-severity stack-based buffer overflow vulnerability in Sentinel Keys Server from Thalesgroup, 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 attacker with a low-privileged account, without any action from a user. The record lists version 1.3.8.0 as the first without the flaw, so updating Sentinel Keys Server 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 Sentinel Keys Server to 1.3.8.0 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Thalesgroup | Sentinel Keys Server | before 1.3.8.0 | 1.3.8.0 |
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
- 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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- 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:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (thalesgroup.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.3 | High | CNA (thalesgroup.com) |
| CVSS 3.1 | 7.8 | High | CNA (thalesgroup.com) |
Official description
Stack-based buffer overflow and out-of-bounds write vulnerability in Thales Sentinel Keys Server on Windows allows Overflow Buffers. Sentinel Keys Server does not check the length of the first field in the input message. A local attacker may craft an input and send it to Sentinel Keys Server. It may lead to code execution as NT AUTHORITY\SYSTEM enabling local privilege escalation. This issue affects Sentinel Keys Server: versions lower than 1.3.8.0.
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 references
Other vulnerabilities in Sentinel Keys Server
- 9.8 Critical severity
Recent Stack-based Buffer Overflow vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.0 High severity
- 8.0 High severity
- 8.8 High severity
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