Attackers Exploit VMware vCenter Vulnerability to Gain Persistent Remote Access
Attackers actively exploit critical VMware vCenter flaw CVE-2026-59310, installing reverse_ssh backdoors on 361 hosts across 47 countries.
QUIRSO observed active exploitation of CVE-2026-59310 (CVSS 9.8), a directory-traversal flaw in VMware vCenter allowing arbitrary code execution, patched by Broadcom in late July. Attack chains deploy a malicious cron job running the open-source reverse_ssh tool for persistence, with compromised systems phoning home starting August 3, five days after disclosure. Forensics show 361 unique victim IPs in 47 countries, mostly Germany, the U.S., Turkey, Iran, and France, with the actor suspected to be an APT. Separately, Defused Cyber reports rising scanning indicative of exploitation of related CVE-2026-59309, an unauthenticated auth bypass in vmdir.
U.S. CISA adds Apple macOS, Microsoft SharePoint, Broadcom VMware vCenter, and Microsoft IKE flaws to its Known Exploited Vulnerabilities catalog
CISA adds actively exploited flaws in Microsoft IKE, SharePoint, VMware vCenter, and macOS Screen Sharing to KEV catalog, due August 21.
CISA added four vulnerabilities to its Known Exploited Vulnerabilities catalog: CVE-2026-33824 (Windows IKE remote code execution, CVSS 9.8), CVE-2026-55040 (SharePoint JWT authentication bypass, CVSS 9.1), CVE-2026-59310 (VMware vCenter Syslog path traversal, CVSS 9.8), and CVE-2026-65400 (macOS Screen Sharing improper authentication). The SharePoint flaw combines four weaknesses including alg:none JWT forging to impersonate any user, with Defused researchers observing attackers using Rapid7's PoC against honeypots. The Dutch NCSC confirmed active exploitation of the macOS Screen Sharing flaw on August 15, 2026. Federal agencies must patch by August 21, 2026.
Suspected China-Nexus Actor Exploits VMware vCenter Flaw, Deploys Babuk
QUIRSO attributes exploitation of VMware vCenter CVE-2026-59310 to a suspected China-nexus actor that hit 361 IPs in 47 countries, deploying backdoors and Babuk.
German incident response firm QUIRSOS assessed with moderate confidence that a suspected China-nexus actor, likely operating in UTC+08:00 hours, exploited VMware vCenter flaw CVE-2026-59310 (CVSS 9.8 directory traversal) beginning five days after Broadcom's July 29 patch. The campaign compromised 361 unique victim IPs across 47 countries, most in Germany, the US, Turkey, Iran, and France. The actor abused cron jobs, a XOR-obfuscated 'linuxFile' WebSocket backdoor with systemd/cron persistence, a JSP web shell, SSH authorized-keys manipulation, and a reverse SSH tool, with one Babuk deployment reported. A separate vCenter 'vcenter_admin' account creation consistent with CVE-2026-59309 exploitation was also observed from August 1.
CISA: Critical VMware RCE flaw now exploited by ransomware gangs
CISA warns ransomware gangs now exploit critical VMware vCenter syslog RCE CVE-2026-59310, already KEV-listed after APT compromises across 47 countries.
Broadcom patched critical directory traversal flaw CVE-2026-59310 in the vCenter Syslog server on July 29, warning of unauthenticated remote code execution. QUIRSO subsequently found 361 compromised IPs across 47 countries after a suspected APT deployed a reverse SSH tool for persistence and remote access. CISA added the flaw to its KEV catalog with a three-day patch deadline for federal agencies, and over the weekend updated it to flag active abuse by ransomware gangs. Shadowserver tracks over 450 exposed vCenter servers, and CISA has tagged 26 VMware vulnerabilities as exploited in the wild over five years, nine abused by ransomware.
Three Critical VMware Flaws Allow Auth Bypass, Code Execution, and VM Escape
Broadcom patches three critical VMware flaws, including vCenter auth bypass CVE-2026-59309 and an ESX VM escape, urging immediate updates.
Broadcom issued emergency updates for VMware ESX, vCenter, Workstation and Fusion, fixing five flaws including CVE-2026-59309 (CVSS 9.8 authentication bypass in vCenter) and CVE-2026-59310 (CVSS 9.8 directory traversal allowing code execution). CVE-2026-47876 (CVSS 9.3) is an out-of-bounds write in the ESX VMXNET3 adapter that permits a virtual machine escape to the host. Broadcom found no evidence of exploitation, but Defused Cyber reported a spike in vCenter scanning on August 11, 2026 consistent with exploitation attempts against CVE-2026-59309 (VMSA-2026-0006). No workarounds are available.
Critical macOS, SharePoint, vCenter, and Microsoft IKE Flaws Under Active Exploitation
CISA added four critical actively exploited flaws to KEV: macOS Screen Sharing, SharePoint, VMware vCenter, and Microsoft IKE, with APT and ransomware use.
CISA added CVE-2026-65400 (macOS Screen Sharing, CVSS 9.8), CVE-2026-55040 (SharePoint, CVSS 9.1), CVE-2026-59310 (VMware vCenter, CVSS 9.8) and CVE-2026-33824 (Microsoft IKE Service Extensions, CVSS 9.8) to the KEV catalog. The macOS flaw was abused to deliver a Monero miner, while the vCenter bug was exploited by a suspected China-nexus APT to install reverse_ssh backdoors and Babuk-derived ransomware across 361 victim IPs in 47 countries. Unit 42 linked CVE-2026-33824 to a Chinese-speaking actor running an AI-enabled campaign using DeepSeek. FCEB agencies must patch by August 21, 2026 under BOD 26-04.
⚡ Weekly Recap: VMware Exploits, Windows 0-Day, MCP Attacks, Browser Hijacks and More
Weekly recap: suspected China-nexus APT exploited VMware vCenter CVE-2026-59310, Lazarus used Windows zero-day CVE-2026-68820, and macOS flaw dropped Monero miners.
The week's top stories included a suspected China-nexus APT exploiting VMware vCenter CVE-2026-59310 (CVSS 9.8), a directory-traversal flaw enabling arbitrary code execution, with backdoors, reverse SSH and Babuk-derived ransomware deployed, per QUIRSO. NCSC-NL reported active exploitation of macOS Screen Sharing flaw CVE-2026-65400 (CVSS 9.8) to install Monero miners on systems with port 5900 exposed. Lazarus Group exploited Windows zero-day CVE-2026-68820 (CVSS 7.0) in Operation Dream Job, delivering ForestTiger and Troy backdoors to defense and aerospace targets. GeoServer patched a critical SQL injection flaw exploited within hours of disclosure, and Jamf analyzed the new Amnesia Stealer for macOS with live browser control.