[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fdJTzEV5aqnMz_TSimwKst3t7tDnQfMaiprrSuVqCsSM":3},{"article":4,"iocs":46},{"id":5,"title":6,"slug":7,"summary":8,"ai_summary":9,"brief":10,"full_text":11,"url":12,"image_url":13,"published_at":14,"ingested_at":15,"relevance_score":16,"entities":17,"category_id":28,"category":29,"article_tags":33},"d0230e0a-2873-4af2-bc9a-19e7a5c7ed40","New Zapscape KVM Flaw Could Let Privileged L1 Guest Code Escape to Linux Hosts","new-zapscape-kvm-flaw-could-let-privileged-l1-guest-code-escape-to-linux-hosts-76d72c","Zapscape, a new Linux kernel vulnerability, could allow an attacker with kernel privileges inside an L1 guest virtual machine (VM) to escape KVM isolation and execute code on the host. The risk applies when nested virtualization is exposed to untrusted guests. The flaw is tracked as CVE-2026-64561 and affects KVM\u002Fx86's shadow memory management unit (MMU), which manages shadow page","A newly disclosed Linux kernel vulnerability, dubbed Zapscape (CVE-2026-64561), allows an attacker with kernel privileges in an L1 guest VM to escape KVM isolation and execute code on the host. The flaw affects KVM\u002Fx86's shadow MMU and is a use-after-free bug that can lead to a full host escape with root privileges. A fix has been merged upstream, and affected Linux distributions are releasing patches.","New Zapscape KVM flaw allows L1 guest code to escape to Linux hosts.","New Zapscape KVM Flaw Could Let Privileged L1 Guest Code Escape to Linux Hosts Swati KhandelwalAug 06, 2026Virtualization Security \u002F Linux Zapscape, a new Linux kernel vulnerability, could allow an attacker with kernel privileges inside an L1 guest virtual machine (VM) to escape KVM isolation and execute code on the host. The risk applies when nested virtualization is exposed to untrusted guests. The flaw is tracked as CVE-2026-64561 and affects KVM\u002Fx86's shadow memory management unit (MMU), which manages shadow page tables used for nested guest memory translation. Security researcher Hyunwoo Kim, who disclosed the bug, said the demonstrated exploit path can run commands on the host with kernel, or root, privileges. The upstream fix has been merged, and administrators running KVM hosts that expose nested virtualization to untrusted guests should update to a fixed stable kernel or a vendor package that backports the patch. The required L1 kernel privilege usually means guest root. Intel systems also require both EPT page-walk length 4 and 5 to be exposed to the L1 guest. AMD has no equivalent condition. Zapscape is a stale-root check ordering flaw in KVM's shadow-MMU bookkeeping that can lead to a use-after-free. During guest-triggered page fault handling, KVM can reclaim MMU pages and invalidate the shadow MMU root page still being used by the fault-handling path. Because the path does not check the root again, KVM can continue under the invalidated root. In a technical write-up, Kim described the issue as a use-after-free in the recursive zap path used when KVM reclaims shadow pages. KVM checked whether the current root was stale before making more MMU pages available. Reclaim could then invalidate that same root, but KVM continued the fault path and created child shadow pages under it. Those child pages inherited the invalid state from the parent and were still placed on KVM's active MMU page list. Later cleanup could attach the same list link to two lists at once, then free the page while stale list references remain, creating a dangling link and post-free write. Kim's public proof-of-concept uses that primitive to build a full chain that creates a root-owned file named \u002FZapscape on the host running the vulnerable KVM. The proof-of-concept targets AMD nested SVM\u002FNPT on Linux 7.1.3. Kim recommends running it under QEMU TCG for safe testing. QEMU is not the vulnerable component. Kim said the bug lives in in-kernel KVM and is triggered independently of QEMU's emulation. Kim's August 6 write-up includes a public proof-of-concept, but it does not claim the flaw has been exploited in the wild. Kim also described it as \"not a weaponized exploit that runs immediately\" in cloud environments, saying real-world use would require moving the L1 actions into a guest kernel module and adapting the exploit to the host kernel configuration and memory backend. The National Vulnerability Database lists Linux 5.9 and later as affected until fixed stable releases, including 6.6.148, 6.12.101, 6.18.42, 7.1.6, and 7.2-rc5. Red Hat assigned a preliminary CVSS score of 7.0 in its advisory and classified the issue as CWE-825, or expired pointer dereference. Package status depends on each Linux vendor's tracker, not only upstream version strings. Red Hat cautions that its packages often carry backported fixes without rebasing to a new upstream version. As of August 6, 2026, Debian's tracker listed bullseye, bookworm, and trixie kernel packages, including their security repositories, as vulnerable. It also listed forky as vulnerable and sid as fixed at 7.1.6-1. According to the disclosure timeline, Kim reported the issue to security@kernel.org on July 11, 2026. A patch was posted and merged on July 21, the issue was submitted to the linux-distros list on August 1 under a five-day embargo, and CVE-2026-64561 was assigned on August 4. Public disclosure followed on August 6. The fix, merged as commit 2abd5287f083, moves the stale-root check after make_mmu_pages_available(). If reclaim invalidates the current root, KVM now restarts the fault with RET_PF_RETRY instead of continuing to map or fetch under the invalid root. The disclosure follows Kim's earlier KVM work, including Januscape (CVE-2026-53359), a separate KVM\u002Fx86 shadow-MMU issue covered by The Hacker News in July, and ITScape (CVE-2026-46316), a KVM\u002Farm64 escape published in June. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  Cloud security, Kernel Security, linux, privilege escalation, Virtualization Security, Vulnerability ⚡ Top Stories This Week New Bit2Watt Attack Could Let Cloud Tenants Disrupt Power Grids Without an Exploit Open-Source Android AI Agents Could Let Invisible Screen Text Run Code on Host PCs Critical SharePoint RCE CVE-2026-50522 Under Active Exploitation After Public PoC AWS Kiro Flaw Let a Poisoned Web Page Rewrite Its Config and Run Code Apple Fixes Hide My Email Bug That Exposed Real Addresses in Mail Logs Microsoft Azure DevOps MCP Flaw Lets Hidden PR Comments Hijack AI Review Agents OpenAI Says Its AI Models Escaped Sandbox, Targeted Hugging Face to Cheat Benchmark Adobe Acrobat Extension Flaw Let Malicious Sites Read WhatsApp Web Data Ubuntu snap-confine Flaw Could Give Local Users Root on Default Desktop Installs Nine-Year-Old RefluXFS Linux Flaw Gives Local Users Root on Default RHEL Installs Attackers Weaponize GitHub Actions Runners to Target cPanel and WHM Servers Claude Cowork Flaw Could Let AI Agent Escape Its VM and Access Mac Files ThreatsDay: Android Spyware, PLC Attacks, AI Image Prompt Injection + 12 More Stories Kimi K3 Agents Found Redis Zero-Days and Built RCE Exploit, Researchers Say Hacker Runs Hermes AI Agent Unattended for Post-Exploitation at Thai Finance Ministry ChatGPT AgentForger Flaw Could Deploy Rogue Workspace Agents via a Phishing Link Certighost Exploit Lets Low-Privileged Active Directory Users Impersonate a Domain Controller Researcher Publishes GitLab RCE PoC Letting Authenticated Users Run Commands as Git Fastjson 1.x RCE Vulnerability Targeted in Attacks With No Patched Available Malvertising Sends Malware in Pieces, Then Makes the Browser Build the Executable ⭐ Featured Resources [Webinar] How Militaries Can Trust the Data Behind Autonomous Missions Download the 5-Step Action Plan for AI-Speed Exploitation Get the Checklist for Gaining Control of AI Use Across Your Organization Get the 2026 CISO Benchmark Report Based on 600 Security Leaders","https:\u002F\u002Fthehackernews.com\u002F2026\u002F08\u002Fnew-zapscape-kvm-flaw-could-let.html","https:\u002F\u002Fblogger.googleusercontent.com\u002Fimg\u002Fb\u002FR29vZ2xl\u002FAVvXsEj5BBX-j7uA7NqPF9tVWhx3y09F3whJ3zweRoWGyI2kJDxhW6ymOG1oumq5Oz0sZWtCAKSCALcd9TTl7Kf5Mo3aqE3aWKH8jfKWt2uUD-CUa6tmid-3MvMTM08EAEhg5iLQ2mlEgFkVeuVKv1QkRqr2T0Ya9JcNtMYheggInGndCG0n-N7BPjyH9vbKCg8\u002Fs1600\u002FZapscape.gif","2026-08-06T17:58:30+00:00","2026-08-06T20:00:22.910506+00:00",8,[18,21,24,26],{"name":19,"type":20},"KVM","product",{"name":22,"type":23},"Nested Virtualization","technology",{"name":25,"type":23},"Shadow MMU",{"name":27,"type":20},"Linux","80544778-fabb-4dcd-aa35-17492e5dcf4f",{"id":28,"icon":30,"name":31,"slug":32},null,"Vulnerabilities","vulnerabilities",[34,36,41],{"category":35},{"id":28,"icon":30,"name":31,"slug":32},{"category":37},{"id":38,"icon":30,"name":39,"slug":40},"c70f3a41-2f0c-4608-870d-b8cbcd8be076","Cloud Security","cloud-security",{"category":42},{"id":43,"icon":30,"name":44,"slug":45},"e7b231c8-5f79-4465-8d38-1ef13aea5a14","Threat Intelligence","threat-intelligence",[47,51],{"type":48,"value":49,"context":50},"cve","CVE-2026-64561","Zapscape KVM vulnerability identifier",{"type":52,"value":53,"context":54},"mitre_attack","T1068","Exploitation for Privilege Escalation (implied by root access)"]