{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23401 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23401 is a medium-severity use after free vulnerability in Linux kernel, published on 1 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-23401 and fix it if it is affected.\n\nWhat it is: CVE-2026-23401 is a medium-severity use after free vulnerability in Linux kernel, published on 1 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-23401 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-23401/ (Markdown: https://insights.sbomify.com/CVE-2026-23401/index.md)","id":"CVE-2026-23401","markdown":"https://insights.sbomify.com/CVE-2026-23401/index.md","name":"CVE-2026-23401","record":{"aliases":["AZL-81354","BELL-CVE-2026-23401","DEBIAN-CVE-2026-23401","GHSA-2g4m-3wvw-crq2","ROOT-OS-DEBIAN-12-CVE-2026-23401","ROOT-OS-DEBIAN-13-CVE-2026-23401","ROOT-OS-UBUNTU-2204-CVE-2026-23401","ROOT-OS-UBUNTU-2404-CVE-2026-23401","UBUNTU-CVE-2026-23401"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel KVM","requires_auth":"low_privilege","summary":"A use-after-free in KVM MMIO SPTE handling allows attackers to cause kernel warnings or potential privilege escalation via guest page faults.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE\n\nWhen installing an emulated MMIO SPTE, do so *after* dropping/zapping the\nexisting SPTE (if it's shadow-present).  While commit a54aa15c6bda3 was\nright about it being impossible to convert a shadow-present SPTE to an\nMMIO SPTE due to a _guest_ write, it failed to account for writes to guest\nmemory that are outside the scope of KVM.\n\nE.g. if host userspace modifies a shadowed gPTE to switch from a memslot\nto emulted MMIO and then the guest hits a relevant page fault, KVM will\ninstall the MMIO SPTE without first zapping the shadow-present SPTE.\n\n  ------------[ cut here ]------------\n  is_shadow_present_pte(*sptep)\n  WARNING: arch/x86/kvm/mmu/mmu.c:484 at mark_mmio_spte+0xb2/0xc0 [kvm], CPU#0: vmx_ept_stale_r/4292\n  Modules linked in: kvm_intel kvm irqbypass\n  CPU: 0 UID: 1000 PID: 4292 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:mark_mmio_spte+0xb2/0xc0 [kvm]\n  Call Trace:\n   \u003cTASK\u003e\n   mmu_set_spte+0x237/0x440 [kvm]\n   ept_page_fault+0x535/0x7f0 [kvm]\n   kvm_mmu_do_page_fault+0xee/0x1f0 [kvm]\n   kvm_mmu_page_fault+0x8d/0x620 [kvm]\n   vmx_handle_exit+0x18c/0x5a0 [kvm_intel]\n   kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm]\n   kvm_vcpu_ioctl+0x2d5/0x980 [kvm]\n   __x64_sys_ioctl+0x8a/0xd0\n   do_syscall_64+0xb5/0x730\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n  RIP: 0033:0x47fa3f\n   \u003c/TASK\u003e\n  ---[ end trace 0000000000000000 ]---","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE","id":"CVE-2026-23401","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":7,"next":{"headline":"KVM: x86/mmu: Only WARN in direct MMUs when overwriting shadow-present SPTE","id":"CVE-2026-23402"},"packages":[],"prev":{"headline":"rust_binder: call set_notification_done() without proc lock","id":"CVE-2026-23400"},"products":["Linux"],"published":"2026-04-01","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-07-15","vendors":["Linux"]},"summary":"A use-after-free in KVM MMIO SPTE handling allows attackers to cause kernel warnings or potential privilege escalation via guest page faults.","url":"https://insights.sbomify.com/CVE-2026-23401/"}