{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-64283 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-64283 is a high-severity vulnerability in Linux kernel, published on 25 Jul 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-2026-64283 and fix it if it is affected.\n\nWhat it is: CVE-2026-64283 is a high-severity vulnerability in Linux kernel, published on 25 Jul 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-2026-64283 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-2026-64283/ (Markdown: https://insights.sbomify.com/CVE-2026-64283/index.md)","id":"CVE-2026-64283","markdown":"https://insights.sbomify.com/CVE-2026-64283/index.md","name":"CVE-2026-64283","record":{"aliases":["BELL-CVE-2026-64283","DEBIAN-CVE-2026-64283","GHSA-64fq-x7r6-wc9g","ROOT-OS-UBUNTU-2204-CVE-2026-64283","UBUNTU-CVE-2026-64283"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","other"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel KVM","requires_auth":"low_privilege","summary":"An integer overflow in KVM guest_memfd binding allows bypassing size checks, potentially leading to memory corruption or denial of service.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7,"severity":"high","source":"nvd","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-190","name":"Integer Overflow or Wraparound"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: guest_memfd: Treat memslot binding offset+size as unsigned values\n\nWhen binding a memslot to a guest_memfd file, treat the offset and size as\nunsigned values to fix a bug where the sum of the two can result in a false\nnegative when checking for overflow against the size of the file.  Passing\nunsigned values also avoids relying on somewhat obscure checks in other\nflows for safety, and tracks the offset and size as they are intended to be\ntracked, as unsigned values.\n\nOn 64-bit kernels, the number of pages a memslot contains and thus the size\n(and offset) of its guest_memfd binding are unsigned 64-bit values.  Taking\nthe offset+size as an loff_t instead of a uoff_t inadvertently converts\nthe unsigned value to a signed value if the offset and/or size is massive.\n\nLocally storing the offset and size as signed values is benign in and of\nitself (though even that is *extremely* difficult to discern), but\noperating on their sum is not.\n\nFor the offset, KVM explicitly checks against a negative value, which might\nseem like a bug as KVM could incorrectly reject a legitimate binding, but\nthat's not actually the case as KVM_CREATE_GUEST_MEMFD takes a signed value\nfor its size, i.e. a would-be-negative offset is also greater than the\nmaximum possible size of any guest_memfd file.\n\nRegarding the size, while KVM lacks an explicit check for a negative value,\ni.e. seemingly has a flawed overflow check, KVM restricts the number of\npages in a single memslot to the largest positive signed 32-bit value:\n\n        if (id \u003c KVM_USER_MEM_SLOTS \u0026\u0026\n            (mem-\u003ememory_size \u003e\u003e PAGE_SHIFT) \u003e KVM_MEM_MAX_NR_PAGES)\n                return -EINVAL;\n\nand so that maximum \"size\" will ever be is 0x7fffffff000.\n\nThe sum of the two is, however, problematic.  While the size is restricted\nby KVM's memslot logic, the offset is not, i.e. the offset is completely\nunchecked until the \"offset + size \u003e i_size_read(inode)\" check.  If the\noffset is the (nearly) largest possible _positive_ value, then adding size\nto the offset can result in a signed, negative 64-bit value.  When compared\nagainst the size of the file (guaranteed to be positive), the negative sum\nis always smaller, and KVM incorrectly allows the absurd offset.\n\nOpportunistically add missing includes in kvm_mm.h (instead of relying on\nits parents).","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: guest_memfd: Treat memslot binding offset+size as unsigned values","id":"CVE-2026-64283","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"integer_overflow","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits","id":"CVE-2026-64284"},"packages":[],"prev":{"headline":"KVM: arm64: Don't leak PFN when kvm_translate_vncr() races MMU notifier","id":"CVE-2026-64282"},"products":["Linux"],"published":"2026-07-25","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":"2026-10-21","vendors":["Linux"]},"summary":"An integer overflow in KVM guest_memfd binding allows bypassing size checks, potentially leading to memory corruption or denial of service.","url":"https://insights.sbomify.com/CVE-2026-64283/"}