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.
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
An unknown threat actor exploited a recently disclosed high-severity security flaw impacting Cisco Catalyst SD-WAN as a zero-day at least two months before it was publicly disclosed, according to new findings from Google-owned Mandiant
The ShinyHunters extortion crew exploited an unpatched flaw in Oracle PeopleSoft to break into enterprise systems, steal data, and demand payment to keep it private. The campaign hit universities hardest
Google has released security updates to address 74 vulnerabilities, including one that has come under active exploitation in the wild
Microsoft on Tuesday released a mitigation for a BitLocker bypass vulnerability named YellowKey following its public disclosure last week
Google on Thursday released security updates for its Chrome web browser to address 21 vulnerabilities, including a zero-day flaw that it said has been exploited in the wild
Amazon Threat Intelligence is warning of an active Interlock ransomware campaign that's exploiting a recently disclosed critical security flaw in Cisco Secure Firewall Management Center (FMC) Software
A recently disclosed security flaw patched by Microsoft may have been exploited by the Russia-linked state-sponsored threat actor known as APT28, according to new findings from Akamai
A newly disclosed maximum-severity security flaw in Cisco Catalyst SD-WAN Controller (formerly vSmart) and Catalyst SD-WAN Manager (formerly vManage) has come under active exploitation in the wild as part of malicious activity that dates back to 2023
A maximum severity security vulnerability in Dell RecoverPoint for Virtual Machines has been exploited as a zero-day by a suspected China-nexus threat cluster dubbed UNC6201 since mid-2024, according to a new report from Google Mandiant and Google Threat Intelligence Group (GTIG)
Google on Friday released security updates for its Chrome browser to address a security flaw that it said has been exploited in the wild
Microsoft on Monday issued out-of-band security patches for a high-severity Microsoft Office zero-day vulnerability exploited in attacks
Cisco has released fresh patches to address what it described as a "critical" security vulnerability impacting multiple Unified Communications (CM) products and Webex Calling Dedicated Instance that it has been actively exploited as a zero-day in the wild
Google on Wednesday released security updates for the Chrome web browser to address four vulnerabilities, including one that it said has been exploited in the wild
Samsung has released its monthly security updates for Android, including a fix for a security vulnerability that it said has been exploited in zero-day attacks
Apple has released security updates to address a security flaw impacting iOS, iPadOS, and macOS that it said has come under active exploitation in the wild
A now-patched security flaw in Google Chrome was exploited as a zero-day by a threat actor known as TaxOff to deploy a backdoor codenamed Trinper
Fortinet has patched a critical security flaw that it said has been exploited as a zero-day in attacks targeting FortiVoice enterprise phone systems
Threat actors with links to the Play ransomware family exploited a recently patched security flaw in Microsoft Windows as a zero-day as part of an attack targeting an unnamed organization in the United States
Enterprise data backup platform Commvault has revealed that an unknown nation-state threat actor breached its Microsoft Azure environment by exploiting CVE-2025-3928 but emphasized there is no evidence of unauthorized data access