Angry bug hunter with Microsoft beef drops new Windows 0-day

They are angry at Redmond and will have their revenge. Nightmare Eclipse, the prolific bug hunter and possibly disgruntled ex-Microsoft employee, disclosed another zero-day vulnerability just hours after Redmond issued a record-breaking number of CVEs and fixes for June Patch Tuesday. The latest zero-day, RoguePlanet, targets Microsoft Defender and works against fully patched Windows 10 and Windows 11 systems, according to the researcher, who also released proof-of-concept exploit code for the security flaw. Assuming the attacker can win a race condition, this bug allows local privilege escalation and leads to SYSTEM-level control over an affected machine. Nightmare Eclipse (aka Chaotic Eclipse) is a disgruntled bug hunter with a deep understanding of Windows and an even deeper grudge against Microsoft. They claim to be an ex-employee, and accuse Redmond of ignoring vulnerability reports and refusing to communicate with them. "When I actively asked you to communicate with me, you refused, humiliated me and made sure to insult me in front of people," they wrote in an earlier blog post that also promised a “bone shattering” drop on July 14. "You defame me in public with your CVE-2026-45585 advisory even though you literally deleted the Microsoft account I used to report bugs to you with and I got zero pennies from doing so and I still happily did like an idiot," the post continued. Possibly as an outlet for this anger, and reportedly in response to Redmond's lack of action, Nightmare began releasing their findings to the public. RoguePlanet marks the seventh Microsoft zero-day that they found and disclosed - accompanied by either a PoC exploit or technical details - before Redmond issued a fix. Microsoft's initial response to those disclosures was widely interpreted as a threat of legal action, prompting massive outrage from the broader infosec community before Redmond sought to calm the backlash by stating it had "no intention to pursue action against individuals conducting or publishing security research." As of Tuesday, the previous six zero-days all have patches. Three of them, RedSun, UnDefend, and BlueHammer, came under attack soon after Nightmare published working exploit code for each and before Microsoft released security updates to address the flaws. The other three, YellowKey, GreenPlasma, and MiniPlasma, all have been fixed as of June’s Patch Tuesday. YellowKey (aka CVE-2026-45585) is a security feature bypass bug in Windows BitLocker. An attacker with physical access to the vulnerable system could bypass the BitLocker Device Encryption feature and gain access to the device's encrypted data. GreenPlasma (aka CVE-2026-45586) and MiniPlasma (aka CVE-2020-17103) are both privilege escalation flaws in the Collaborative Translation Framework (CTFMON) and the Cloud Files Mini Filter Driver that can be abused by an authorized attacker to elevate privileges locally and gain SYSTEM access. When asked about RoguePlanet, a Microsoft spokesperson told The Register that the Windows giant is “aware of the reported vulnerability and is actively investigating the validity and potential applicability of these claims." The spokesperson continued: "Microsoft is committed to investigating security issues and updating impacted products to protect customers as soon as possible. Importantly, we support coordinated vulnerability disclosure, an industry standard that protects customers and supports the research community by ensuring their findings are thoroughly investigated and addressed before being made public." Soon after Nightmare published a PoC for RoguePlanet, the ThreatLocker threat intelligence team validated the exploit code and said that they were “actively assessing impact, affected systems, and additional mitigations,” promising to share more findings “as they become available.” Tharros Labs senior vulnerability analyst and long-time respected security sleuth Will Dormann said he tested the exploit code, too. “It's reportedly not 100% reliable, but it worked on the first attempt for me,” Dormann wrote. Nightmare, for their part, rolled back the promise of a “bone shattering” drop on July 14. “(Un)fortunately I will be unable to mass disclose zerodays in July 14th, RoguePlanet took way more time than expected and truly drained me,” the researcher said on Tuesday. “I might take a break but I can't say for sure what I will be doing for next month, maybe it's nothing, maybe it's smtg. But the big thing is not happening. I did not intend to spread a mass panic with that post and I apologize for doing so.”®