Recent ZyXEL Switch Vulnerability Exploited by Chinese Hackers

A Chinese threat actor has been targeting vulnerable ZyXEL GS1900 switches worldwide for sensitive information exfiltration, threat intelligence firm GreyNoise warns.

Tracked as CVE-2026-7273 (CVSS score of 8.8), the security defect is described as a stack-based buffer overflow that could be exploited without authentication to execute OS commands via crafted HTTP requests.

ZyXEL rolled out security updates patching the bug in ten GS1900 switch models in June. On Monday, GreyNoise warned that it was exploited by a Chinese hacking group in August against ZyXEL devices in 48 countries.

The threat actor used a heavily obfuscated Python script to exfiltrate sensitive information such as hashed root credentials, configuration details, and networking information from 996 vulnerable devices.

“While the script explicitly targets firmware versions 2.10-2.90 of the GS1900-24, it does provide command-line options (e.g., libc base address, global offsets) for targeting other firmware in scope for the vulnerability,” GreyNoise says.

While the hackers extracted hashed credentials, 564 of the compromised devices had factory default credentials, leaving the door open to future attacks.

On Monday, the US cybersecurity agency CISA added CVE-2026-7273 to its Known Exploited Vulnerabilities (KEV) catalog, urging federal agencies to patch it within three days, as mandated by BOD 26-04.

The same threat actor was also seen using a chain of Ubiquiti vulnerabilities leading to remote code execution (RCE), and targeting WordPress installations in July, in attacks against small business and government entities.

“The most egregious data theft occurred against an identified western governmental organization involving more than 18,000 sensitive records stolen from its backend database,” GreyNoise says.

The cybersecurity firm believes that the threat actor is the same as or closely related to the Red Heron hacking group that Acronis observed exploiting a Gitea vulnerability in attacks targeting hundreds of systems worldwide.

Related: WordPress Patches ‘Click2Shell’ Vulnerability

Related: Organizations Warned of 3 Exploited Linux Kernel Vulnerabilities

Related: In Other News: Ransomware Developer Sentenced, Plugin4Shell AI Attack, Critical SAP Flaw

Related: CISA Retires Weekly Vulnerability Bulletin in Risk-Based Pivot

WordPress Patches ‘Click2Shell’ Vulnerability

The bug lets attackers automatically install and preview themes and could lead to remote code execution.

Organizations Warned of 3 Exploited Linux Kernel Vulnerabilities

Attackers could exploit the flaws to cause denial-of-service conditions, disclose memory, or modify memory.

Artificial Intelligence

AI-Built Exploit and Sign-In Flaw Opened Path to Internal OpenAI Code

Hacktron researchers earned a bug bounty after demonstrating access to OpenAI employee accounts.

Artificial Intelligence

Microsoft Patches 18 Vulnerabilities in AI, Cloud Products

Microsoft fixed vulnerabilities across Azure and AI-branded products, with privilege escalation flaws accounting for the majority.

Critical Orkes Conductor Vulnerability Exploited in Attacks

CVE-2026-58138 is an unauthenticated remote code execution vulnerability that attackers can exploit via inline workflow definitions.

Check Point, Kaspersky, Tanium Patch Product Vulnerabilities

Check Point Security Management and Log Servers are affected by a critical vulnerability that can allow remote code execution with root privileges.

CISA Retires Weekly Vulnerability Bulletin in Risk-Based Pivot

The decision follows BOD 26-04, which directs federal organizations to prioritize vulnerabilities based on real-world risk.

ISC Patches 14 Vulnerabilities in BIND 9 Security Update

Attackers could exploit the flaws to increase resource usage, trigger an unexpected program exit, or terminate the named process.