{"id":106562,"date":"2026-07-27T12:53:12","date_gmt":"2026-07-27T08:53:12","guid":{"rendered":"https:\/\/techxmedia.com\/en\/?p=106562"},"modified":"2026-07-27T12:53:14","modified_gmt":"2026-07-27T08:53:14","slug":"qualys-uncovers-critical-linux-vulnerability","status":"publish","type":"post","link":"https:\/\/techxmedia.com\/en\/qualys-uncovers-critical-linux-vulnerability\/","title":{"rendered":"Qualys Uncovers Critical Linux Vulnerability"},"content":{"rendered":"\n

Linux vulnerability researcher Qualys<\/a> has announced the discovery of CVE-2026-64600, dubbed “RefluXFS,” a critical flaw in the Linux kernel identified through a structured research initiative between the Qualys Threat Research Unit (TRU) and Anthropic’s Claude Mythos Preview. The vulnerability enables local privilege escalation to root on affected systems.<\/p>\n\n\n\n

According to Qualys<\/a>, RefluXFS is a race condition in the Linux kernel’s XFS filesystem copy-on-write path. It allows an attacker with an ordinary local account to overwrite protected files on disk and gain host root privileges. The flaw affects deployments running SELinux in Enforcing mode.<\/p>\n\n\n\n

The company said the Linux vulnerability has existed since Linux kernel version 4.11, released in 2017. It could potentially affect more than 16.4 million systems worldwide. These include deployments running Red Hat Enterprise Linux (RHEL), Oracle Linux, Amazon Linux, and Fedora.<\/p>\n\n\n\n

“This discovery emerged from a structured research initiative between Qualys and Anthropic, where we integrated Claude Mythos Preview into our manual audit workflow to accelerate our research while maintaining strict human oversight,” said Saeed Abbasi, Head of the Qualys Threat Research Unit (TRU).<\/p>\n\n\n\n

“This human-validated, AI-accelerated approach let us surface a complex kernel race condition while holding to the strict accuracy and responsible-disclosure standards expected. Every finding here cleared the same evidence bar we apply to any Qualys security advisory,” Abbasi added.<\/p>\n\n\n\n

Qualys explained that RefluXFS enables an unprivileged local user to overwrite the on-disk contents of any readable file on a reflink-enabled XFS volume. The company said this capability can directly lead to host root privileges.<\/p>\n\n\n\n

Furthermore, Qualys stated that exploitation is highly reliable and leaves no kernel log output. It also noted that on-disk modifications remain in place even after a system reboot.<\/p>\n\n\n\n

“We rate RefluXFS as an emergency priority because exploitation could begin from ordinary local privileges. The vulnerability is present in standard enterprise kernel builds, and a successful exploitation provides host root. The exploitation works under common kernel hardening settings, and fixed kernels are available,” Abbasi said.<\/p>\n\n\n\n

Qualys urged organizations to install vendor-supplied kernel updates as soon as they become available. It also recommended rebooting affected systems after patching to ensure workloads start on the updated kernel. In addition, the company advised organizations to prioritize exposed and multi-tenant systems for remediation.<\/p>\n\n\n\n

Vendor-fixed kernels are now available and are being backported to enterprise Linux distributions. However, Qualys said there are currently no reliable or practical mitigations or temporary configuration changes that can reduce the risk before patching.<\/p>\n\n\n\n

Qualys has also published further technical details covering affected Linux distributions, proof-of-concept information, detection methods, and remediation guidance. Organizations are encouraged to review these resources and deploy available updates promptly to protect against the Linux vulnerability.<\/p>\n","protected":false},"excerpt":{"rendered":"

Linux vulnerability researcher Qualys has announced the discovery of CVE-2026-64600, […]<\/p>\n","protected":false},"author":8,"featured_media":106563,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1595,9621],"tags":[966],"contributor":[9732],"class_list":["post-106562","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-cybersecurity","category-emerging-technologies","tag-qualys","contributor-news-desk"],"featured_image_src":"https:\/\/techxmedia.com\/en\/wp-content\/uploads\/2026\/07\/Qualys.jpg.jpeg","author_info":{"display_name":"Rabab","author_link":"https:\/\/techxmedia.com\/en\/author\/rabab\/"},"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t