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Nightmare Eclipse Drops ‘HardBreacher’ Kaspersky Product Exploit

Feeds.Feedburner •Eduard Kovacs • August 31, 2026

The researcher known as Nightmare Eclipse has dropped another zero-day — this time a privilege escalation exploit targeting a Kaspersky endpoint security product.

Nightmare Eclipse, also known as Chaotic Eclipse , has released PoC exploits for many vulnerabilities in recent months, mainly Windows and Microsoft Defender flaws.

The researcher started dropping zero-days after growing frustrated with Microsoft’s handling of vulnerability reports. While many of the exploits remained at the PoC stage, a few ended up being exploited in the wild by malicious actors.

Over the weekend, Nightmare Eclipse released an exploit targeting a privilege escalation vulnerability in Kaspersky Endpoint Security. The exploit has been dubbed HardBreacher .

“The PoC is not in the best shape at all, it is basically duct tapped, I just managed to make it work and that’s all,” the researcher noted.

“The interesting part this is the Kaspersky completely loses it when you take control over the UI process, you can cause it to stop functioning, grant/block access to files its not supposed to, if the PoC succeeds, the entire operating system becomes a hot mess,” the researcher added.

Contacted by SecurityWeek , Kaspersky said the underlying issue has been resolved.

“The corresponding fix is delivered via an automatic update, or users can trigger a database update manually,” Kaspersky stated.

Other exploits made public recently by Nightmare Eclipse include ShieldBreak , which allows an attacker to spawn a shell with System privileges, and LegacyHive , which enables privilege escalation.

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Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Nightmare Eclipse Releases Kaspersky Exploit 'HardBreacher' A researcher known as Nightmare Eclipse has released a proof-of-concept (PoC) exploit named HardBreacher, targeting a privilege escalation vulnerability in Kaspersky Endpoint Security. This exploit affects fully patched Windows 11 systems running Kaspersky Endpoint v14.0.0.504. The PoC is described as unstable and may require multiple attempts to execute successfully. When successful, it can create a DLL file in System32 with full user permissions, potentially disrupting Kaspersky's functionality and compromising system security. Kaspersky has stated that the underlying issue has been resolved through an automatic update. However, the exploit remains unverified and has not been assigned a CVE by Kaspersky. The researcher has a history of releasing exploits after criticizing vendors' responses to vulnerability reports, raising concerns about responsible disclosure practices. 6 sources 58

Extracted Entities

Nightmare Eclipse Drops ‘HardBreacher’ Kaspersky Product Exploit

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Extracted Entities

Attack Types (1)

CWE Weaknesses (1)

MITRE ATT&CK (1)

Platforms (2)

Vulnerabilities (2)