The US Cybersecurity and Infrastructure Security Agency (CISA) has warned that threat actors are actively exploiting vulnerabilities in IBM Langflow OSS, N-able N-central, and Apache Tomcat, adding all of them to its Known Exploited Vulnerabilities (KEV) catalog.

Langflow OSS chain enables unauthenticated RCE

The most severe of the group, CVE-2026-9198 (CVSS 9.8), affects IBM Langflow OSS and allows unauthenticated attackers to achieve remote code execution by chaining two API endpoints. According to IBM, one endpoint issued superuser bearer tokens to any network caller, while a second endpoint executed arbitrary Python code submitted for validation. An attacker could obtain a superuser token from the auto-login endpoint, then use it to submit malicious code to the validation endpoint. IBM disclosed the flaw and patched it on July 17 in Langflow OSS version 1.10.1, warning that all default deployments are affected. Proof-of-concept code surfaced about a week later, and CISA added the CVE to KEV on August 4.

N-able N-central authentication bypass exploited as zero-day

CVE-2026-18556 (CVSS 7.4) is an authentication bypass in N-able’s N-central remote monitoring and management platform. N-able says threat actors exploited it as a zero-day to gain administrative access and connect to systems managed through the platform. The initial fix proved incomplete, and attackers bypassed it, prompting N-able to issue a hotfix and a second CVE, CVE-2026-18577, as exploitation intensified in late July. Both CVEs are now listed in CISA’s KEV catalog.

Tomcat EncryptInterceptor bypass tied to Chinese threat activity

The third addition, CVE-2026-34486 (CVSS 7.5), is an EncryptInterceptor bypass in Apache Tomcat, patched in April. The issue stems from a fix for an earlier padding oracle flaw, CVE-2026-29146, introduced in March. According to researchers at StrigaAI, who identified the bug, the patch moved a single line of code that turned the encryption layer from fail-closed to fail-open, opening a path to unauthenticated remote code execution on every node in a Tomcat cluster using the optional EncryptInterceptor feature. Instead of rejecting messages that failed decryption, the flawed logic forwarded attacker-controlled code up the interceptor chain unmodified.

SOCRadar reported last week that CVE-2026-34486 has been exploited by a Chinese threat actor using the Snowlight malware family, while Palo Alto Networks separately observed the same vulnerability being exploited in an AI-enabled autonomous hacking campaign attributed to Chinese hackers.

Patch deadline for federal agencies

Under Binding Operational Directive 26-04, CISA is requiring federal civilian agencies to remediate all four vulnerabilities, CVE-2026-9198, CVE-2026-18556, CVE-2026-18577, and CVE-2026-34486, by August 7. Organizations running affected Langflow OSS, N-central, or Tomcat cluster deployments should apply available patches immediately regardless of sector.