Is CVE-2026-78402 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-78402 being exploited in the wild.

How severe is CVE-2026-78402?

High severity, with a CVSS score of 7.8, published 30 October 2026.

Which products and versions are affected?

Thales Sentinel Keys Server versions lower than 1.3.8.0.

Is there a fix for CVE-2026-78402?

Yes: fixed in 1.3.8.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-78402 attacked?

It is attacked with local access, in a network appliance.

Am I affected by CVE-2026-78402?

Check whether you run Thales Sentinel Keys Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-78402: Thales Sentinel Keys Server stack-based buffer overflow

CVE-2026-78402 · Severity: high · CVSS 7.8 · Published 2026-10-30

Thales Sentinel Keys Server, a software security appliance for managing cryptographic keys, contains a buffer overflow vulnerability on Windows. A local attacker can exploit this to execute code with system-level privileges, potentially gaining complete control of the affected machine and accessing or manipulating all cryptographic keys stored on it.

Vendors: Thales.

Quick answers

Is CVE-2026-78402 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-78402 being exploited in the wild.
How severe is CVE-2026-78402?: High severity, with a CVSS score of 7.8, published 30 October 2026.
Which products and versions are affected?: Thales Sentinel Keys Server versions lower than 1.3.8.0.
Is there a fix for CVE-2026-78402?: Yes: fixed in 1.3.8.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-78402 attacked?: It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-78402?: Check whether you run Thales Sentinel Keys Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 1.3.8.0

Technical details

A stack-based buffer overflow and out-of-bounds write vulnerability exists in Sentinel Keys Server due to insufficient input validation on the first field of incoming messages. An unauthenticated local attacker can craft malicious input to trigger the overflow, leading to arbitrary code execution with NT AUTHORITY\SYSTEM privileges. The vulnerability is fixed in version 1.3.8.0 and later.

Affected products

Thales Sentinel Keys Server versions lower than 1.3.8.0

Timeline

2026-10-30: disclosed

References

https://supportportal.thalesgroup.com/csm?id=kb_article_view&sys_kb_id=50fc9f3b3b005f10bba8b41864e45a61&sysparm_article=KB0031216

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.