CISA Flags Langflow RCE, Tomcat, and N-central Flaws as Actively Exploited

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added three vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog on August 5, 2026, all confirmed as actively exploited in the wild. Federal civilian agencies (FCEB) are required to apply patches for all three by August 7, 2026 — a tight 48-hour window reflecting the severity and urgency of ongoing attacks.

The Three Vulnerabilities

CVE-2026-9198 — Langflow Unauthenticated RCE

Langflow, the popular open-source low-code platform for building AI agent workflows, has been hit by yet another critical RCE vulnerability. CVE-2026-9198 (CVSS 9.8) allows unauthenticated attackers to inject and execute arbitrary code on Langflow servers.

Langflow reached a patch in version 1.10.1 (released July 2026), but the platform has been "repeatedly weaponized" by threat actors in recent months. Researchers linked active exploitation to Chinese-speaking threat actors operating under the aliases knaithe, KnYuan, and believed to originate from Zhuhai. These actors deployed autonomous AI-enabled attack frameworks — specifically the DeepSeek/Hermes Agent framework — to conduct automated attacks against 460+ endpoints across multiple countries.

In parallel, a separate China-nexus group deployed SNOWLIGHT malware against 107 endpoints across 100+ nations, leveraging the same Langflow attack surface.

Patch: Upgrade to Langflow 1.10.1 or later immediately.

CVE-2026-34486 — Apache Tomcat Missing Encryption

Apache Tomcat versions affected by CVE-2026-34486 (CVSS 7.5) fail to encrypt communications between cluster members in multi-node deployments. This allows an attacker with network access between cluster nodes to intercept or tamper with inter-cluster traffic — potentially leading to session hijacking, data exposure, or remote code execution depending on the traffic content.

Patches were available in:

• Tomcat 11.0.21
• Tomcat 10.1.54
• Tomcat 9.0.117

All three were released in April 2026, making this a case of organizations running unpatched software more than three months after a fix was available.

Patch: Upgrade to the appropriate patched version for your Tomcat branch.

CVE-2026-18556 — N-able N-central Authentication Bypass

N-able N-central, a widely-deployed remote monitoring and management (RMM) platform, is affected by a critical authentication bypass tracked as CVE-2026-18556 (CVSS 8.2). The flaw allows unauthenticated attackers to bypass authentication controls and access the platform as a privileged user.

Complicating the situation: the initial patch was incomplete, spawning a second related CVE — CVE-2026-18577 (also CVSS 8.2) — covering the residual bypass path that the first fix missed. Organizations should confirm they have applied patches addressing both CVEs, not just the original advisory.

Patch: Apply the latest N-central security update addressing both CVE-2026-18556 and CVE-2026-18577.

Why This Matters: AI-Enabled Autonomous Attacks

The Langflow exploitation activity is particularly noteworthy. CISA's and affiliated researchers' analysis identified that threat actors used autonomous AI agent frameworks — specifically DeepSeek and the Hermes Agent system — to automate vulnerability exploitation at scale. Rather than manually exploiting each target, the actors deployed AI-driven agents that could scan, exploit, and compromise Langflow instances across hundreds of endpoints with minimal human intervention.

This represents a documented escalation in how state-linked threat actors leverage AI to amplify exploitation campaigns. The Langflow platform's own AI-building capabilities make it an attractive target: a successful compromise of a Langflow instance can give attackers access to the AI workflows, credentials, and connected systems that the platform manages.

Federal Deadline and Broader Impact

CISA's August 7, 2026 patch deadline for FCEB agencies underscores the urgency. While the KEV catalog formally applies only to federal civilian agencies, CISA consistently recommends that all organizations — private sector included — treat KEV catalog additions as high-priority remediation targets.

Organizations running any of these three products should:

1. Langflow: Upgrade to 1.10.1+ and audit logs for signs of prior exploitation (unauthorized code execution, unusual API calls)
2. Apache Tomcat: Apply the relevant patch for your version branch; review cluster network segmentation to limit exposure while patching
3. N-able N-central: Apply patches for both CVE-2026-18556 and CVE-2026-18577; audit for unauthorized session creation or privilege escalation indicators

Key Takeaways

• CISA added three actively exploited CVEs to the KEV catalog on August 5, 2026
• Langflow RCE (CVSS 9.8) is being exploited by Chinese-linked actors using autonomous AI agent frameworks across hundreds of targets globally
• Apache Tomcat cluster encryption flaw patches have been available since April 2026 — organizations should have already applied them
• N-able N-central auth bypass required two separate CVEs due to an incomplete initial patch; apply fixes for both
• Federal agencies have until August 7, 2026 — all organizations should treat this as a priority remediation window

References

• CISA KEV Catalog
• The Hacker News — CISA Flags Langflow RCE, Tomcat, and N-central Flaws
• NVD — CVE-2026-9198 (Langflow)
• NVD — CVE-2026-34486 (Apache Tomcat)
• NVD — CVE-2026-18556 (N-able N-central)