The security tool that's supposed to stop privilege escalation is the one doing the privilege escalation.
RoguePlanet is a confirmed, publicly weaponized Microsoft Defender zero-day — a race condition in Defender's file remediation logic that hands an attacker SYSTEM privileges on fully patched Windows 10 and 11. No CVE assigned. No patch. The June 2026 Patch Tuesday updates, which dropped hours before this disclosure, don't touch it.
The timing is not accidental. The researcher — Nightmare Eclipse (@deadeclipse666) — published RoguePlanet at approximately 7 PM ET on June 9, within hours of Patch Tuesday closing. This is the cadence. GreenPlasma and YellowKey, two BitLocker zero-days from the same researcher, also landed today. RoguePlanet is the fifth confirmed zero-day in a campaign that has now moved systematically through BitLocker, Windows core components, and Microsoft Defender. Each disclosure is PGP-signed. The blog is live. ThreatLocker's CEO Danny Jenkins independently reproduced it on video — Windows 11, KB5094126 installed, 100% reliable on that configuration. This is not a fabrication.
The original vulnerability was worse. Nightmare Eclipse's own write-up confirms RoguePlanet started as remote code execution: coerce a victim to open a malicious .vhd(x) from an SMB share, Defender overwrites its own files, RCE follows via junction attack. Microsoft silently patched mpengine! SysIO* in mid-May, closing that path without public acknowledgment. The researcher spent three weeks rewriting the exploit to still reach SYSTEM via LPE. The RCE variant's patch status remains ambiguous — Microsoft has said nothing about it publicly.
The race condition's variable success rate on different hardware is real but not the operative finding. The operative finding is that the June 2026 patches don't close this, and a working PoC is sitting on a self-hosted git platform at
projectnightcrawler.dev — available to anyone, no friction. It's self-hosted because GitHub and GitLab have already removed the researcher's prior work at Microsoft's request. The threat of legal action, including an MSRC post thinly warning researchers against "malicious activity causing real harm," achieved the opposite of its intended effect. You pressure a researcher into building their own distribution infrastructure, the PoC library outlasts whatever legal posture you take. It always does.
The MITRE mapping is straightforward: T1068 (Exploitation for Privilege Escalation) via the race condition, T1548 (Abuse Elevation Control Mechanism) riding Defender's own SYSTEM context, T1553 (Subvert Trust Controls) because the escalation vector is the security tooling itself. The original RCE path maps to T1190 (Exploit Public-Facing Application) via SMB coercion — that variant's closure is unconfirmed.
The immediate risk is high for any Windows environment running Defender as primary endpoint protection without application allowlisting. LPE-to-SYSTEM is the post-exploitation workhorse. Ransomware affiliates and initial access brokers use it to complete privilege chains after phishing or credential stuffing delivers a low-privilege foothold. RoguePlanet is a clean, publicly available tool that closes that gap in one step.
There is no patch. The current best-available mitigation is application allowlisting — ThreatLocker's own statement is that their allowlisting blocks the exploit's execution chain, which aligns with MITRE D3FEND M1038. Organizations running Defender without that layer are exposed until Microsoft ships a fix.
The medium-term picture is the broader campaign. The researcher claims additional memory corruption vulnerabilities in Defender, plus separate batches in "several other components." The
projectnightcrawler.dev repository distributes working exploits regardless of what happens next. The floor dropped out from under organizations that assumed this month's patches closed the Defender risk surface. It hadn't opened yet.