All news with #zero day exploitation tag

⚠️A new zero-day called YellowKey, published this week by a researcher using the alias Nightmare-Eclipse, demonstrates a reliable bypass of default Windows 11 BitLocker deployments. The exploit circumvents disk encryption that relies solely on the TPM-stored key and requires physical access to the affected machine. Organizations that mandate BitLocker, including government contractors, should reassess device physical security and BitLocker configuration.

🔒 At Pwn2Own Berlin (May 14–16), researchers uncovered 47 zero-day vulnerabilities and shared almost $1.3 million in prize money, with Devcore taking $505,000. The enterprise-focused competition targeted AI databases, coding agents, LLM toolchains and NVIDIA products. Notable wins included exploits against VMware ESXi, Microsoft Exchange, SharePoint and a sandbox escape on Microsoft Edge. ZDI will disclose the findings to vendors, who have 90 days to patch.

🛡️Chaotic Eclipse has published a proof-of-concept for a Windows privilege escalation zero-day, dubbed MiniPlasma, which targets the Cloud Files Mini Filter Driver (cldflt.sys) in the HsmOsBlockPlaceholderAccess routine. Originally reported to Microsoft in September 2020 and linked to CVE-2020-17103, the researcher says the exact issue remains unpatched. Tests show it can spawn a SYSTEM shell on fully patched Windows 11 systems running May 2026 updates, though success rates vary due to a race condition.

🏆 The Pwn2Own Berlin 2026 contest at OffensiveCon (May 14–16) awarded security researchers $1,298,250 for exploiting 47 zero-day vulnerabilities across browsers, enterprise apps, servers, virtualization, containers, LLMs and local privilege escalation. Competitors earned $523,000 on day one, $385,750 on day two, and $389,500 on day three. DEVCORE topped the leaderboard with $505,000 and 50.5 Master of Pwn points; Cheng‑Da Tsai secured the highest single payout of $200,000 for an Exchange RCE chain.

🔒 A researcher known as Chaotic Eclipse published a proof-of-concept exploit and a compiled executable for a Windows privilege escalation zero-day named MiniPlasma. The researcher says the issue affects the cldflt.sys Cloud Filter driver and an undocumented CfAbortHydration API, and claims the bug traces back to a 2020 report (CVE-2020-17103). BleepingComputer tested the PoC on a fully patched Windows 11 Pro system (May 2026 updates) and reproduced SYSTEM-level access. Microsoft has been contacted for comment.

⚠️Microsoft has warned of a zero-day cross-site scripting vulnerability in Exchange Outlook Web Access (OWA) that can be triggered by a specially crafted email. The flaw (CVE-2026-42897) is being actively exploited and affects Exchange Server 2016, 2019, and Server Subscription Edition, while Exchange Online is unaffected. Microsoft has published an automatic mitigation via the Exchange EM Service; administrators should enable EM Service or run the Exchange on-premises Mitigation Tool (EOMT) if servers are air-gapped. The interim mitigations can disrupt OWA features such as calendar printing and inline image display, and a formal security update will be released later.

🔒 During day two of Pwn2Own Berlin 2026 at OffensiveCon (May 14–16), competitors earned $385,750 by exploiting 15 unique zero-day vulnerabilities across enterprise products, including Windows 11, Microsoft Exchange, and Red Hat Enterprise Linux. Cheng-Da Tsai (Orange Tsai) earned $200,000 by chaining three bugs to achieve remote code execution as SYSTEM on Exchange, while other researchers demonstrated privilege escalations on Windows and RHEL and exploited the NVIDIA Container Toolkit. The AI category also saw multiple successes against coding agents such as Cursor AI and OpenAI Codex. Under Pwn2Own rules all targets run the latest patched OS versions and vendors receive a 90-day disclosure window to issue fixes.

⚠️ Microsoft has disclosed a high-severity zero-day, CVE-2026-42897, in on-premises Exchange Server that could allow an attacker to execute arbitrary code by sending a specially crafted email to an Outlook user. The flaw is an XSS vulnerability affecting all supported versions of Exchange 2016, 2019 and Subscription Edition, but not Exchange Online. Microsoft recommends enabling the Exchange Emergency Mitigation (EM) Service, which is applied by default, and provides an alternative manual mitigation via the Exchange On-premises Mitigation Tool for air-gapped environments while patches are developed.

⚠ Cisco warns of an actively exploited authentication bypass in Cisco Catalyst SD-WAN Controller (CVE-2026-20182) rated 10.0, affecting on-premises and SD-WAN Cloud Manager deployments. The vulnerability stems from a peering authentication mechanism that "is not working properly" and can grant high-privileged, non-root administrative access and NETCONF control. Cisco detected exploitation in May, released security updates as the only full remediation, and advises restricting management-plane access and reviewing peering and auth logs for IOCs.

🔒 On day one of Pwn2Own Berlin 2026 researchers earned $523,000 exploiting 24 unique zero-days, led by Orange Tsai, who collected $175,000 after chaining four logic flaws to escape the Microsoft Edge sandbox. Windows 11 was rooted three times for new privilege-escalation bugs, and Valentina Palmiotti secured payouts for Red Hat Workstations and an NVIDIA Container Toolkit flaw. The event focuses on enterprise and AI-targeted technologies.

🔥 Palo Alto released fixes for CVE-2026-0300, a critical PAN-OS buffer-overflow exploited in the wild to drop payloads like EarthWorm and ReverseSocks5. The bulletin also highlights new and recurring threats including zero-auth API data leaks at an AI training vendor, an FCC extension for router updates, supply-chain contests, and sophisticated phishing campaigns. Several incidents employ weaponized attachments, tokenizer tampering in AI models, and open-source tools to achieve stealthy remote access and long-term persistence.

🔒 An anonymous researcher known as Chaotic Eclipse (aka Nightmare-Eclipse) disclosed two new Windows zero-days: YellowKey, a BitLocker bypass present in the Windows Recovery Environment (WinRE), and GreenPlasma, a CTFMON-related privilege escalation. YellowKey targets Windows 11 and Windows Server 2022/2025 by placing crafted FsTx files on a USB or EFI partition and replaying them to obtain a shell even when BitLocker is enabled. The GreenPlasma proof-of-concept can create arbitrary memory section objects in SYSTEM-writable directories, potentially enabling higher-privilege manipulation, though the exploit is incomplete. Microsoft says it investigates reported issues and supports coordinated disclosure.

🔒 A researcher known as Chaotic Eclipse (Nightmare-Eclipse on GitHub) published proof-of-concept exploits named YellowKey and GreenPlasma that bypass BitLocker protections and enable local privilege escalation on affected Windows versions. YellowKey abuses the Windows Recovery Environment (WinRE) and NTFS transaction replay to spawn a shell and access encrypted volumes, while GreenPlasma allows arbitrary memory-section creation that can be escalated to SYSTEM. The author said the disclosures were driven by dissatisfaction with Microsoft's handling of reports. Microsoft says it investigates and supports coordinated disclosure.

🔒 Anthropic's Mythos Preview, shared last month with a limited set of security partners, has demonstrated the ability to autonomously find zero-day vulnerabilities across major operating systems and browsers. Anthropic paired the release with Project Glasswing and $100 million in usage credits to help defenders, but reports of unauthorized access and denied requests from Chinese entities have already emerged. The development challenges the assumption of a durable US lead and has injected cybersecurity into high-level US–China summit talks, prompting urgent questions about access, regulation, and international cooperation.

🔍 Microsoft disclosed MDASH, an AI-driven vulnerability discovery system that found 16 previously unknown Windows flaws, including four critical remote code execution bugs that were patched as part of the May 12 Patch Tuesday release. Built by the Autonomous Code Security and Windows Attack Research teams, the platform orchestrates more than 100 specialized AI agents across multiple models to scan, validate and construct triggering inputs before human review. Microsoft said MDASH is intentionally model-agnostic and will enter private enterprise preview next month.

⚠ copy.fail is a severe Linux kernel local privilege escalation disclosed on 29 April 2026 with a working proof-of-concept. It abuses the kernel crypto API (AF_ALG sockets) together with splice() to write four bytes at a time directly into the page cache of files the attacker does not own, leaving on-disk files unchanged. The exploit works unmodified across Ubuntu, RHEL, Debian, SUSE, Amazon Linux and Fedora, bypasses checksum-based monitoring, and has no race or per-distro offsets; the mainline fix landed on 1 April and distros are rolling patches.

🔒 Researchers report that a threat actor known as Mr_Rot13 is exploiting a critical cPanel/WHM vulnerability (CVE-2026-41940) to deploy a cross-platform backdoor named Filemanager on compromised hosts. A QiAnXin XLab analysis indicates automated attacks from more than 2,000 source IPs worldwide and an infection chain that replaces root credentials, plants SSH keys, deploys a PHP web shell, and delivers a Go-based infector. The malware harvests credentials and system data, sends results to attacker-controlled infrastructure, and enables file management and remote command execution across Windows, macOS, and Linux.

🛡️ Google disclosed detection of an unknown threat actor using a zero-day exploit likely developed with an AI model, marking the first observed malicious application of AI for vulnerability discovery and exploit generation. GTIG said the exploit was a Python script implementing a 2FA bypass in a widely used open-source web administration tool and contained hallmarks of LLM-generated code. Google worked with the vendor to patch the flaw, disabled malicious assets, and linked the activity to a broader set of AI-enabled abuse campaigns including the Android backdoor PromptSpy.

🔍 Google Threat Intelligence Group (GTIG) reports a rapid shift from nascent AI-enabled operations to industrial-scale use of generative models by threat actors. Based on Mandiant incident response, Gemini telemetry, and GTIG research, the report documents AI-assisted zero-day exploit development, autonomous malware like PROMPTSPY, and advanced obfuscation techniques. It highlights supply chain targeting of AI environments, anonymized premium LLM access, and specific interest from PRC- and DPRK-linked clusters. The report also outlines mitigations and defensive AI uses.

🔍 Google’s Threat Intelligence Group (GTIG) reports the first observed case of cybercriminals using AI to discover and weaponize a zero-day, targeting a popular open-source web-based system administration tool to bypass two-factor authentication. GTIG worked with the vendor to close the flaw and disrupt the campaign. Forensic analysis of the Python exploit showed AI-like traits—structured docstrings, Pythonic formatting, and a hallucinated CVSS score. Google noted the attackers did not use Gemini or Anthropic Mythos.