3 new KEV entries: IBM Langflow and what else CISA flagged

On 2026-08-04 CISA added three entries to the Known Exploited Vulnerabilities (KEV) catalog: an unauthenticated remote code execution in IBM Langflow, an encryption bypass in Apache Tomcat that chains into a prior RCE, and the second half of an N-able N-central authentication bypass pair. Together with a Cisco Secure Firewall Management Center hard-coded password flaw added the week before, the batch paints a clear picture: attackers are hitting management planes, AI orchestration stacks, and long-lived Java middleware, and CISA has evidence that each is being exploited in the wild.

This post covers what each flaw is, how CISA's KEV process defines "actively exploited," how to check whether your estate is affected, and what to do within the Binding Operational Directive 22-01 remediation window that governs federal civilian agencies (and that most private-sector programs mirror by policy).

The four flaws, in defender's terms

CVE-2026-9198: IBM Langflow, unauthenticated RCE. Langflow is a visual builder for LLM pipelines. CISA's KEV entry describes a code injection vulnerability that lets unauthenticated attackers execute arbitrary code remotely on default Langflow deployments. "Default deployment" is the key phrase: this is not a hardened-configuration edge case. If Langflow was stood up to prototype an internal agent and then forgotten on a VM behind a permissive security group, that host is open to immediate takeover.

CVE-2026-34486: Apache Tomcat, EncryptInterceptor bypass, chainable with CVE-2025-24813. The KEV note confirms this is a missing-encryption flaw against the EncryptInterceptor, chainable with CVE-2025-24813. That earlier Tomcat CVE is the partial-PUT deserialization RCE from 2025. In practice, a cluster relying on EncryptInterceptor to keep inter-node traffic confidential loses that guarantee under this attack, and any operator who dismissed CVE-2025-24813 as "internal only, mTLS between nodes" needs to revisit that assumption.

CVE-2026-18556 and CVE-2026-18577: N-able N-central, authentication bypass via alternate path. These two are linked. CVE-2026-18556 was added 2026-08-04; CVE-2026-18577 was added the day before and is explicitly the result of an incomplete patch for CVE-2026-18556, enabling authentication bypass and account takeover. N-central is an MSP-grade RMM console. An account takeover here is not a single-tenant compromise; it is a supply-chain foothold into every managed endpoint the console reaches.

CVE-2026-20316: Cisco Secure Firewall Management Center, hard-coded password. Added 2026-07-29. FMC (formerly Firepower Management Center) governs the firewall estate. The KEV description says an unauthenticated remote attacker can log in with a low-privileged account using the hard-coded credential and reach sensitive data. Low-privileged read access to a firewall management plane is a reconnaissance goldmine: rule sets, object groups, VPN topology, and change history.

Why "KEV" is a stronger signal than "critical CVSS"

The KEV catalog is not a severity ranking. CISA adds an entry only when it has reliable evidence of active exploitation, the CVE is assigned, and a clear remediation exists. That evidentiary bar is what makes KEV useful for prioritization: unlike a raw CVSS score, a KEV listing means attackers are exploiting the flaw now. Under BOD 22-01, federal civilian agencies must remediate KEV entries by the due date CISA sets, typically two to three weeks from the add date. Private-sector teams that mirror the same posture through policy or contract should treat 2026-08-25 as the working deadline for the 2026-08-04 additions and 2026-08-19 for the Cisco FMC entry.

Fast triage: are you affected?

Start with asset inventory, not scanning. Scanners will find Tomcat instances and the FMC. They may miss the shadow Langflow that a data-science team stood up on an EC2 instance last quarter. Two commands worth running:

# Langflow: find processes and containers by name and default port 7860
ps -eo pid,cmd | grep -iE 'langflow|uvicorn.*langflow' | grep -v grep
docker ps --format '{{.Names}}\t{{.Image}}\t{{.Ports}}' | grep -iE 'langflow|:7860'
ss -tlnp | awk '$4 ~ /:7860$/'

# Tomcat: version, and whether the EncryptInterceptor is configured
find / -name catalina.sh 2>/dev/null -exec sh -c '"$1" version' _ {} \;
grep -RIn --include='server.xml' 'EncryptInterceptor' /opt /etc /var /usr/local 2>/dev/null

For N-central, check the vendor-supplied version string in the console footer against the fixed build in N-able's security advisory for CVE-2026-18577 (the incomplete-patch CVE); anything that only received the CVE-2026-18556 fix is still vulnerable. For Cisco FMC, version checks alone are insufficient. Review authentication logs for the low-privileged account name Cisco identifies in its advisory and flag any successful logins from outside your management VLAN.

What "remediate" means for each

Track the deadline, not the ticket

The recurring failure mode is not "we did not know about the KEV entry." It is "we opened a ticket, assigned it, and the ticket outlived the CISA due date." KEV additions deserve their own SLA board, wired to asset inventory, with a named owner per platform (Java middleware, RMM, firewall management, AI tooling). Two weeks is not much time to find every shadow Langflow. Start now.

Verifiable security.