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.
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. [...]
Cisco has released security updates to address a vulnerability in the Catalyst SD-WAN Manager, tracked as CVE-2026-20262, that was exploited in attacks to escalate to root privileges. [...]
Oracle is warning about a critical PeopleSoft Suite zero-day vulnerability tracked as CVE-2026-35273 that allows unauthenticated remote code execution, with the flaw actively exploited in ShinyHunter data theft attacks. [...]
On Thursday, Cisco warned of a high-severity, unpatched zero-day in the Cisco Catalyst SD-WAN Manager (tracked as CVE-2026-20245) actively exploited in attacks enabling root privilege escalation. [...]
Cisco is warning that a critical Catalyst SD-WAN Controller authentication bypass flaw, tracked as CVE-2026-20182, was actively exploited in zero-day attacks that allowed attackers to gain administrative privileges on compromised devices. [...]
The critical CVE-2026-41940 authentication bypass vulnerability in cPanel, WHM, and WP Squared is being actively exploited in the wild and has been leveraged in attempts since late February. [...]
Adobe has released an emergency security update for Acrobat Reader to fix a vulnerability, tracked as CVE-2026-34621, that has been exploited in zero-day attacks since at least December. [...]
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has released new details about RESURGE, a malicious implant used in zero-day attacks exploiting CVE-2025-0282 to breach Ivanti Connect Secure devices. [...]
Cisco is warning that a critical authentication bypass vulnerability in Cisco Catalyst SD-WAN, tracked as CVE-2026-20127, was actively exploited in zero-day attacks that allowed remote attackers to compromise controllers and add malicious rogue peers to targeted networks. [...]
Ivanti has disclosed two critical vulnerabilities in Ivanti Endpoint Manager Mobile (EPMM), tracked as CVE-2026-1281 and CVE-2026-1340, that were exploited in zero-day attacks. [...]
Fortinet has confirmed a new, actively exploited critical FortiCloud single sign-on (SSO) authentication bypass vulnerability, tracked as CVE-2026-24858, and says it has mitigated the zero-day attacks by blocking FortiCloud SSO connections from devices running vulnerable firmware versions. [...]
Cisco has fixed a critical Unified Communications and Webex Calling remote code execution vulnerability, tracked as CVE-2026-20045, that has been actively exploited as a zero-day in attacks. [...]
The U.S. Cybersecurity & Infrastructure Security Agency (CISA) is warning government agencies to patch an Oracle Identity Manager tracked as CVE-2025-61757 that has been exploited in attacks, potentially as a zero-day. [...]
An advanced threat actor exploited the critical vulnerabilities "Citrix Bleed 2" (CVE-2025-5777) in NetScaler ADC and Gateway, and CVE-2025-20337 affecting Cisco Identity Service Engine (ISE) as zero-days to deploy custom malware. [...]
Gladinet has released security updates for its CentreStack business solution to address a local file inclusion vulnerability (CVE-2025-11371) that threat actors have leveraged as a zero-day since late September. [...]
Oracle has silently fixed an Oracle E-Business Suite vulnerability (CVE-2025-61884) that was actively exploited to breach servers, with a proof-of-concept exploit publicly leaked by the ShinyHunters extortion group. [...]
Oracle has silently fixed an Oracle E-Business Suite vulnerability (CVE-2025-61884) that was actively exploited to breach servers, with a proof-of-concept exploit publicly leaked by the ShinyHunters extortion group. [...]
Threat actors are exploiting a zero-day vulnerability (CVE-2025-11371) in Gladinet CentreStack and Triofox products, which allows a local attacker to access system files without authentication. [...]
Oracle is warning about a critical E-Business Suite zero-day vulnerability tracked as CVE-2025-61882 that allows attackers to perform unauthenticated remote code execution, with the flaw actively exploited in Clop data theft attacks. [...]
Citrix fixed three NetScaler ADC and NetScaler Gateway flaws today, including a critical remote code execution flaw tracked as CVE-2025-7775 that was actively exploited in attacks as a zero-day vulnerability. [...]