Zero-Day | Breaking Cybersecurity News | The Hacker News

Microsoft on Tuesday released fixes for a record 206 security vulnerabilities impacting its software portfolio, including three flaws that have been publicly disclosed at the time of release. Of the 206 flaws, 39 are rated Critical, and 167 are rated Important in severity. This includes 63 privilege escalation, 56 remote code execution, 30 information disclosure, 27 spoofing, 20 security feature bypass, seven denial-of-service, and three tampering vulnerabilities. The patches also include two non-Microsoft CVEs, a privilege escalation vulnerability impacting Windows Kernel ( CVE-2025-10263 ) and a UEFI Secure Boot security feature bypass ( CVE-2026-8863 ). They are in addition to more than 350 security flaws that Google has addressed in Chromium, which is used in Microsoft's Edge browser. Topping the list of fixes is CVE-2026-45657 (CVSS score: 9.8), a use-after-free flaw affecting Windows Kernel that could result in remote code execution. "An attacker could exploi...

The anonymous security researcher going by the name Chaotic Eclipse (aka Nightmare-Eclipse) has released a proof-of-concept (PoC) exploit for yet another Microsoft Defender zero-day named RoguePlanet . "The exploit is a race condition, so it's a hit or miss," the researcher, who published the exploit under a new GitHub account "MSNightmare" said . "I have managed to get a 100% success rate on some machines while it struggled to work on others." Should the exploit succeed, the result is a shell with SYSTEM-level privileges, granting the attacker the ability to run arbitrary code or perform unauthorized actions. The researcher said the exploit has been tested on Windows 11 and 10 machines with the June 2026 Patch Tuesday updates installed, meaning the exploit works on the up-to-date versions of the desktop operating system. That said, the exploit does not work on Windows Server instances in its current form since "standard users cannot mou...

Google has released security updates to address 74 vulnerabilities, including one that has come under active exploitation in the wild. The high-severity vulnerability, tracked as CVE-2026-11645 (CVSS score: 8.8), has been described as an out-of-bounds memory access in V8, Chrome's JavaScript and WebAssembly engine. "Out-of-bounds read and write in V8 in Google Chrome prior to 149.0.7827.103 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page," reads a description of the flaw in the NIST's National Vulnerability Database (NVD). A security researcher named "303f06e3" has been credited with discovering and reporting the flaw on April 27, 2026. The researcher has been awarded a bug bounty of $55,000 for responsible disclosure. As is customary in these cases, Google acknowledged that an "exploit for CVE-2026-11645 exists in the wild," but stopped short of sharing additional specifics to ensure that a m...

Two things landed within days of each other this week. A security startup reported 21 previously unknown vulnerabilities in FFmpeg, the media library inside almost everything that touches video, all of them found by an autonomous AI agent. The same week, Google shipped Chrome 149 with patches for 429 security bugs, the most ever in a single release. Only the FFmpeg bugs were found by AI. Chrome's record landed after Google overhauled its bounty program to cope with a flood of AI-generated reports. The mechanisms differ, but the pressure is the same: AI is putting more vulnerabilities in front of the people who have to deal with them, and faster than before. The FFmpeg findings come from depthfirst , whose autonomous security agent scanned the project's roughly 1.5 million lines of C and produced 21 confirmed zero-days, each with a reproducible proof-of-concept input. The company puts the cost of the run at around $1,000. Several of the bugs had been latent for 15 to 2...

Cisco has warned that a high-severity security flaw impacting Catalyst SD-WAN Manager has come under active exploitation. The vulnerability, tracked as CVE-2026-20245 , carries a CVSS score of 7.8 out of a maximum of 10.0. It affects the following deployment types - On-Prem Deployment Cisco SD-WAN Cloud-Pro Cisco SD-WAN Cloud (Cisco Managed) Cisco SD-WAN for Government (FedRAMP) "A vulnerability in the CLI of Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, could allow an authenticated, local attacker to execute arbitrary commands as root by supplying a crafted file to the affected system," Cisco said in an advisory. The network security company said the vulnerability is the result of insufficient validation of user-supplied input, which an attacker could exploit by uploading a crafted file to the affected system. This, in turn, could permit the attacker to perform command injection attacks and elevate their privileges as the root user. "To...

A now-patched high-severity security flaw affecting Digital Knowledge KnowledgeDeliver , a Learning Management System (LMS) popular in Japan, was exploited as a zero-day to deliver the Godzilla web shell and ultimately facilitate the deployment of Cobalt Strike Beacon. The vulnerability, tracked as CVE-2026-5426 (CVSS score: 7.5), stems from the use of hard-coded ASP.NET machine keys, leading to unauthenticated remote code execution via a ViewState deserialization attack. The abuse of publicly disclosed ASP.NET machine keys by threat actors was first documented by Microsoft in February 2025. "An unknown threat actor leveraged this access to inject malicious code into the LMS platform, with the goal of infecting users visiting the site," Google Mandiant and Google Threat Intelligence Group (GTIG) said . The security flaw impacted Digital Knowledge KnowledgeDeliver deployments prior to February 24, 2026. It's worth noting that similar vulnerabilities in Sitecore Ex...

Microsoft on Tuesday released a mitigation for a BitLocker bypass vulnerability named YellowKey following its public disclosure last week. The zero-day flaw, now tracked as CVE-2026-45585 , carries a CVSS score of 6.8. It has been described as a BitLocker security feature bypass. "Microsoft is aware of a security feature bypass vulnerability in Windows publicly referred to as 'YellowKey,'" the tech giant said in an advisory. "The proof of concept for this vulnerability has been made public, violating coordinated vulnerability best practices." The issue impacts Windows 11 version 26H1 for x64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows Server 2025, and Windows Server 2025 (Server Core installation). YellowKey was disclosed by a security researcher named Chaotic Eclipse (aka Nightmare-Eclipse). It essentially involves placing specially crafted 'FsTx' files on a USB driv...

Chaotic Eclipse, the security researcher behind the recently disclosed Windows flaws, YellowKey and GreenPlasma , has released a proof-of-concept (PoC) for a Windows privilege escalation zero-day flaw that grants attackers SYSTEM privileges on fully patched Windows systems. Codenamed MiniPlasma , the vulnerability impacts "cldflt.sys," which refers to the Windows Cloud Files Mini Filter Driver, and resides in a routine named "HsmOsBlockPlaceholderAccess." It was originally reported to Microsoft by Google Project Zero researcher James Forshaw in September 2020. Although it was assumed that the shortcoming was fixed by Microsoft in December 2020 as part of CVE-2020-17103 , Chaotic Eclipse said further investigation has uncovered that the "exact same issue [...] is actually still present, unpatched." "I'm unsure if Microsoft just never patched the issue or the patch was silently rolled back at some point for unknown reasons. The original PoC by...

An anonymous cybersecurity researcher who disclosed three Microsoft Defender vulnerabilities has returned with two more zero-days involving a BitLocker bypass and a privilege escalation impacting Windows Collaborative Translation Framework (CTFMON). The security defects have been codenamed YellowKey and GreenPlasma , respectively, by the researcher, who goes by the online aliases Chaotic Eclipse and Nightmare-Eclipse. The researcher described YellowKey as "one of the most insane discoveries I ever found," likening the BitLocker bypass to functioning as a backdoor, as the bug is present only in the Windows Recovery Environment ( WinRE ), a built-in framework designed to troubleshoot and repair common unbootable operating system issues. YellowKey affects Windows 11 and Windows Server 2022/2025. At a high level, it involves copying specially crafted "FsTx" files on a USB drive or the EFI partition, plugging the USB drive into the target Windows computer with Bit...