CISA flags active exploits in OpenSSH, GPUStack, and IBM flaws

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) updated its Known Exploited Vulnerabilities (KEV) catalog on Monday with four high-severity flaws affecting widely used infrastructure components. The agency cited evidence of active exploitation for vulnerabilities in OpenBSD OpenSSH, GPUStack, SignalWire FreeSWITCH, and IBM Aspera Faspex. This update serves as an urgent directive for federal agencies and a strong warning for private sector teams managing these systems.

What happened

CISA’s addition to the KEV catalog highlights immediate threats rather than theoretical risks. The most prominent entry is CVE-2026-123158, known as SSHole, which affects OpenBSD OpenSSH running on Linux. Since November 6, 2026, security firms have recorded 22 exploitation attempts from 14 unique IP addresses. GreyNoise detected the first attempt against its honeypot network on November 7 at 12:46 a.m. UTC. While Defused Cyber noted that the activity is not yet widespread, confirmed post-exploitation actions indicate serious intent. Attackers are conducting reconnaissance, querying cloud metadata services, and attempting to read password hashes and root SSH keys.

The other three vulnerabilities also carry critical CVSS scores of 9.8, except for SSHole which is rated 8.1. CVE-2026-102895 in GPUStack allows unauthenticated administrative access, enabling attackers to change models, create persistent API keys, and execute code. This flaw was fixed in July 2026 after reports of in-the-wild exploitation. CVE-2026-116779 in SignalWire FreeSWITCH permits code injection, leading to credential disclosure and arbitrary command execution, with a fix released in October 2026. Lastly, CVE-2026-123218 in IBM Aspera Faspex allows authenticated users to bypass authorization checks for privilege escalation, patched in November 2026.

Post-exploitation analysis reveals sophisticated tactics. In some cases, a threat actor dubbed GT10 deployed TAC Agent, a Python-based command-and-control tool. This agent performs shell command execution, directory enumeration, and file transfers. WatchTowr has also observed the OpenSSH flaw being used for botnet recruitment and cryptocurrency mining operations. Federal Civilian Executive Branch agencies must apply fixes by November 12, 2026, but the window for all organizations is closing rapidly.

How it works

The SSHole vulnerability stems from an unexpected status code or return value in the OpenSSH authentication process on Linux systems. This logic error allows attackers to bypass authentication mechanisms entirely, granting them access without valid credentials. Once inside, attackers modify the SSH authorized_keys file to maintain persistent access, ensuring they can return even if initial entry points are closed. They also target cloud metadata services to harvest environment secrets and credentials.

In GPUStack, the improper authentication flaw lets unauthenticated users send specific POST requests to the /v2/inference-backends/from-yaml endpoint. This action grants administrative privileges, allowing the creation of persistent API keys and exposure of worker and cloud-provider secrets. For IBM Aspera Faspex, the issue lies in incorrect authorization handling. An authenticated user can craft a specific message that the system fails to validate correctly, thereby escalating their privileges beyond their intended role. These mechanisms rely on subtle implementation errors rather than complex cryptographic breaks, making them difficult to detect without rigorous testing.

Key details

• CVE-2026-123158 (SSHole): Affects OpenBSD OpenSSH on Linux; allows authentication bypass via unexpected status codes; fixed in November 2026.
• CVE-2026-102895: Affects GPUStack; allows unauthenticated admin access and code execution; fixed in July 2026.
• CVE-2026-116779: Affects SignalWire FreeSWITCH; enables code injection and credential disclosure; fixed in October 2026.
• CVE-2026-123218: Affects IBM Aspera Faspex; allows privilege escalation via crafted messages; fixed in November 2026.
• Active Threats: GT10 actor deploys TAC Agent for persistence; watchTowr reports botnet and crypto-mining usage.
• Deadline: Federal agencies must patch by November 12, 2026.

Why it matters

For engineering teams, the presence of these flaws in the KEV catalog shifts the priority from routine maintenance to emergency response. OpenSSH is a foundational component for remote server management, meaning nearly every Linux-based infrastructure is potentially exposed. The fact that attackers are already modifying authorized_keys files suggests they aim for long-term persistence rather than quick hit-and-run attacks. This makes detection harder, as standard login alerts may not trigger if the attacker uses valid-looking key-based authentication after the initial breach.

The GPUStack vulnerability is particularly relevant for AI and ML teams who rely on this package for managing inference backends. Unauthenticated administrative access means attackers can alter model configurations or steal cloud provider secrets stored in the environment. Given that fixes were available months ago for some of these issues, the continued exploitation highlights a gap between patch availability and deployment. Teams must verify not just that patches exist, but that they are applied across all instances, including those in staging or legacy environments.

What you can do

• Immediately patch OpenSSH to the latest version released in November 2026 to mitigate the SSHole vulnerability.
• Update GPUStack to the version fixed in July 2026 and rotate all administrator API keys and cloud provider secrets.
• Apply the October 2026 fix for SignalWire FreeSWITCH and audit call control logs for unauthorized changes.
• Upgrade IBM Aspera Faspex to the November 2026 patch level and review user privilege assignments for anomalies.
• Monitor for modifications to SSH authorized_keys files and query cloud metadata service logs for unusual access patterns.
• Scan for indicators of compromise related to TAC Agent, such as unexpected Python processes or directory enumeration activities.