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.
Broken vdaemon Peering Authentication Enables Unauthenticated Admin AccessA maximum-severity vulnerability in Cisco Catalyst SD-WAN Controller is being actively exploited, giving attackers administrative privileges without authentication. The authentication bypass vulnerability stems from a broken peering authentication mechanism.
During the second day of Pwn2Own Berlin 2026, competitors collected $385,750 in cash awards after exploiting 15 unique zero-day vulnerabilities in multiple products, including Windows 11, Microsoft Exchange, and Red Hat Enterprise Linux for Workstations. [...]
The threat group behind the attacks is also linked to a series of recently disclosed vulnerabilities in the vendor’s firewalls and SD-WAN systems. The post Cisco zero-day under ongoing attack by persistent threat group appeared first on CyberScoop.
The zero-day vulnerability affects on-premises installations for all versions of Exchange Server 2016, 2019 and Subscription Edition
On Thursday, Microsoft shared mitigations for a high-severity Exchange Server vulnerability exploited in attacks that allow threat actors to execute arbitrary code via cross-site scripting (XSS) while targeting Outlook on the web users. [...]
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. [...]
A cybersecurity researcher has published proof-of-concept (PoC) exploits for two unpatched Microsoft Windows vulnerabilities named YellowKey and GreenPlasma, which are a BitLocker bypass and a privilege-escalation flaw. [...]
It's the first time in two years with no zero-days. But with 137 flaws to patch, including nine critical ones, admins still have plenty of work to do.
Google Says Criminals Used AI to Discover and Code ExploitA cybercriminal group came close to launching a mass attack earlier this year, armed with a software exploit that an AI model had built from scratch, said Google researchers. Google said it worked with the affected vendor to patch the flaw before an attack could be launched.
Google on Monday disclosed that it identified an unknown threat actor using a zero-day exploit that it said was likely developed with an artificial intelligence (AI) system, marking the first time the technology has been put to use in the wild in a malicious context for vulnerability discovery and exploit generation
Researchers at Google Threat Intelligence Group (GTIG) say that a zero-day exploit targeting a popular open-source web administration tool was likely generated using AI. [...]
Researchers found artifacts in the code that proved AI was heavily involved. A prominent cybercrime group planned to exploit the zero-day en masse for financial gain. The post Google spotted an AI-developed zero-day before attackers could use it appeared first on CyberScoop.
Google Threat Intelligence Group details how cybercriminals attempted to launch a campaign based around an AI-developed Zero-Day targeting open-source software