Cybersecurity firm GreyNoise has identified a pattern in which spikes in attacker activity frequently occur days before critical vulnerabilities in network devices are publicly disclosed, giving defenders a potential early warning window. Analyzing millions of sessions targeting multiple edge device vendors between late 2025 and early 2026, the company found that roughly half of all observed activity surges were followed by a vulnerability disclosure within about three weeks. On average, attackers appeared to act approximately 11 days before public announcements.

According to GreyNoise, this lead time can provide organizations with a valuable opportunity to prepare defenses, apply patches, and strengthen exposed systems before vulnerabilities become widely known and exploited. One notable case involved a critical flaw in Cisco’s SD-WAN Controller, identified as CVE-2026-20127, which carried a maximum severity rating. In the weeks leading up to its disclosure in February 2026, multiple spikes in suspicious activity were detected, intensifying just days before the vulnerability became public. The issue later prompted urgent warnings from international cybersecurity authorities.

GreyNoise observed a consistent pattern in these incidents. Initial activity often begins as broad scanning across many systems, followed by a sharp increase in targeted traffic from a smaller number of sources. This shift suggests attackers moving from reconnaissance to focused exploitation attempts.

Similar behavior was seen in activity preceding vulnerabilities affecting other major vendors, including SonicWall and several enterprise networking providers. The most common early indicators included large-scale scanning activity, followed by brute-force attempts and remote code execution probes.

The findings highlight a broader trend of attackers identifying and testing vulnerabilities before official disclosures. These early actions may stem from independent discovery, insider knowledge, or analysis of software updates. GreyNoise noted that scanning activity tends to provide the earliest and most reliable signal, often appearing days before more aggressive attack techniques. As activity becomes more concentrated, it may indicate that attackers are narrowing their focus on specific high-value targets With exploitation of network device vulnerabilities rising sharply in recent years, the company emphasized the need for organizations to respond more quickly to unusual activity patterns. Monitoring sudden spikes in scanning or login attempts, especially when combined with increased targeting intensity, can help security teams anticipate potential threats.

The company advised that while these patterns should not be treated as definitive indicators of undisclosed vulnerabilities, they can serve as important signals for heightened vigilance. By acting on these early warnings, organizations may be better positioned to mitigate risks before vulnerabilities are widely exploited.

Recommended Cyber Technology News:

To participate in our interviews, please write to our CyberTech Media Room at info@intentamplify.com