
Citrix NetScaler Under Siege: Third Zero-Day Exploit Emerges in Two Weeks
Citrix disclosed CVE-2026-88779, the third actively exploited NetScaler zero-day vulnerability within a two-week period in December 2024. This high-severity denial-of-service vulnerability affects NetScaler instances with SAML authentication enabled, allowing attackers to crash systems with a single crafted request. While less severe than the previous two zero-days, threat actors are actively exploiting it in the wild and can chain it with CVE-2026-88771 to accelerate attacks. CISA added the vulnerability to its Known Exploited Vulnerabilities catalog, and Citrix has released patches. This incident highlights the escalating threat landscape targeting network edge infrastructure, with organizations facing unprecedented pressure from sophisticated adversaries exploiting zero-day vulnerabilities at an alarming pace.
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