A 0-Day is a software vulnerability without an available fix, creating risk because defenders have limited time to mitigate exploitation.
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Background for this topic.
0-Day describes a software vulnerability unknown to the software maker or unpatched when first exploited. Attackers can use these flaws immediately, as no official fix or signature exists to block the exploit. Such vulnerabilities often affect widely deployed software or hardware, making them valuable for targeted attacks or widespread campaigns.
Because defenders lack patches or reliable detection signatures initially, they must rely on anomaly detection, network monitoring, and threat intelligence to identify suspicious activity linked to 0-day exploits. Rapid patching once a fix is released is critical to reduce exposure. Tracking emerging 0-day threats helps prioritize defensive measures and informs risk management decisions in environments where unpatched vulnerabilities pose significant security risks.
Weekly headline count for the current query.
A security researcher using the "Nightmare Eclipse" handle has released a Windows zero-day exploit dubbed LegacyHive that allows attackers to escalate privileges on up-to-date Windows systems. [...]
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added a newly patched security flaw impacting Microsoft SharePoint Server to its Known Exploited Vulnerabilities (KEV) catalog, requiring Federal Civilian Executive Branch (FCEB) agencies to apply the fixes by July 19, 2026
LegacyHive Is a Local Privilege Escalation BugThe vulnerability hunter in a feud with Microsoft released yet another Windows zero-day Tuesday as promised, though the touted "bone-shattering" disclosure was stripped down to prevent public exploitation. LegacyHive, exploits a profile-loading race condition to access another user's registry hive.
Researchers said the vulnerabilities, which attackers are chaining together, were first exploited three weeks before the vendor disclosed and patched the defects. The post SonicWall customers under threat as attackers exploit 2 zero-days appeared first on CyberScoop.
LegacyHive PoC exposes a Windows Privilege Escalation flaw affecting fully patched Windows desktop and server systems. Just hours after Microsoft’s July 2026 Patch Tuesday, security researcher Nightmare Eclipse, also known as Chaotic Eclipse, published a new Windows zero-day proof-of-concept called LegacyHive. This time, the target is the Windows User Profile Service (ProfSvc), and unlike the […]
Intruder built an AI-powered "vulnerability vending machine" that combines code slicing with LLMs to automatically discover complex software vulnerabilities. The company explains how the system found and exploited a previously unknown WordPress plugin zero-day, with additional discoveries already under responsible disclosure. [...]
Experts say it’s a useful post-compromise tool, for those with the brain cells required to put it together
Security researcher Chaotic Eclipse (aka Nightmare-Eclipse) has released a new proof-of-concept (PoC) exploit called LegacyHive
U.S. Cybersecurity and Infrastructure Security Agency (CISA) adds SonicWall and Microsoft flaws to its Known Exploited Vulnerabilities catalog. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added SonicWall and Microsoft flaws to its Known Exploited Vulnerabilities (KEV) catalog. The flaws added to the catalog are: This week, SonicWall confirmed the active exploitation of two zero-day vulnerabilities […]
SonicWall warns of active attacks exploiting two SMA 1000 zero-days, including a flaw enabling arbitrary command execution. SonicWall confirmed the active exploitation of two zero-day vulnerabilities affecting Secure Mobile Access (SMA) 1000 appliances. The vulnerabilities were internally discovered and reported by Adam Babis of the company’s PSIRT. The company investigated multiple incidents indicating these vulnerabilities […]
SonicWall has warned of active exploitation of two zero-day vulnerabilities impacting Secure Mobile Access (SMA) 1000 series appliances, one of which could be exploited to achieve arbitrary command execution
SonicWall warns that threat actors have been exploiting two SMA1000 vulnerabilities, tracked as CVE-2026-15409 and CVE-2026-15410, in zero-day attacks and urges customers to install the newly released security updates. [...]
Today is Microsoft's July 2026 Patch Tuesday, and with it comes security updates for a record-breaking 570 flaws, including two zero-day vulnerabilities exploited in attacks and one publicly disclosed. [...]
Progress Software has confirmed that a high-severity zero-day vulnerability is behind the emergency shutdown of ShareFile Storage Zone Controllers last week and has released security updates to patch the flaw. [...]
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two maximum-severity security flaws impacting iCagenda and Balbooa extensions for Joomla to its Known Exploited Vulnerabilities (KEV) catalog, following reports of zero-day exploitation in the wild
NightmareEclipse Says Mitigation Can Exhaust Disk Space, Crash AppsMicrosoft's patch for CVE-2026-50656, known as RoguePlanet, has sparked fresh criticism after researcher NightmareEclipse alleged the mitigation can exhaust disk space, crash applications and leak memory, extending a months-long dispute over Microsoft's handling of multiple zero-day disclosures.
The researcher known as "Nightmare-Eclipse" published a proof-of-concept (PoC) exploit for the Windows Defender vulnerability in early June after dropping several other Microsoft zero-days.
Weeks after the exploit code dropped, Redmond has finally ships a fix for the Defender zero-day
Microsoft has released a security patch to address a Defender zero-day vulnerability known as "RoguePlanet," disclosed after the June 2026 Patch Tuesday. [...]
A cybersecurity startup dangling millions of dollars to acquire zero-day security vulnerabilities in popular software is run by a pair of far-right conspiracy theorists and convicted felons whose most recent ventures included fake intelligence companies and a now-defunct AI-based lobbying platform they operated under assumed names.